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Photocatalytic performance for hydrogen evolution. a) PHE rates with different samples under visible light (λ > 420 nm, Na2S/Na2SO3 as a scavenger). b) Time courses of PHE on Cu–ZIS, Pt1/Cu–ZIS, and Pnc/ZIS. Error bars represent standard deviations from triplicate experiments (n = 3). c) Recycling performance for Pt1/Cu–ZIS. d) PHE of Pt1/Cu–ZIS with and without KSCN, indicating that SCN‐ions strongly poison Pt1/Cu–ZIS.
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Single-atom photocatalysts have shown their fascinating strengths in enhancing charge transfer dynamics; however, rationally designing coordination sites by metal doping to stabilize isolated atoms is still challenging. Here, a one-unit-cell ZnIn2S4 (ZIS) nanosheet with abundant Cu dopants serving as the suitable support to achieve a single atom Pt...
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Heterostructure photocatalysts are developed for H2 production from visible light. Because of their excellent photocatalytic hydrogen evolution (PHE), PCs made of CdS and MoS2 have been studied extensively. Important characteristics of PCs to maximize PHE are efficient charge transfer and high surface area. Bacterial cellulose (BC), which is produc...
Citations
... [17] Cocatalyst loading is feasible for resolving the aforementioned dilemma as it facilitates the charge-carrier separation. [18,19] Particularly, constructing the interfacial chemical bond between photocatalyst and cocatalyst provides the rapid channels at the atomic level, which reinforces the interfacial interaction with cocatalyst for accelerating the charge transfer with lower energy barrier. [20,21] The smooth construction of the above structure is highly dependent on the lattice matching between the photocatalyst and the cocatalyst. ...
Maximizing the utilization of photogenerated electrons and holes to drive the coupling reaction of hydrogen evolution with selective value‐added organic synthesis holds great potential for more efficient exploitation of solar energy. Herein, the interstitial boron‐doped CdS is synthesized by taking SiO2 as a template as well as the adsorption sites of boric acid, which contributes to the boron doping and induces the reinforced Cd─Se bonding for enhancing the interfacial interaction with co‐catalyst MoSe2. Thus, the interfacial Cd─Se bond with more electron localization provides rapid channels at the atomic level for accelerating the charge transfer with a lower energy barrier, achieving the efficient hydrogen evolution and high selectivity pyruvic acid synthesis concurrently. This work provides a new perspective in avoiding the use of sacrificial agents uneconomically and producing green hydrogen with high‐value‐added chemicals simultaneously.
... The resulting ZMX-M catalyst, incorporating ZIS-M with MXene, exhibited an exceptional photocatalytic hydrogen evolution rate of 14.82 mmol g −1 h −1 , which is 3.52 times that of pristine ZIS (Figure 2b). This obtained performance exceeds that of most previously reported ZnIn 2 S 4 -based photocatalysts [30][31][32][33][34][35][36][37][38][39][40][41] (Figure 2c; Table S1 Supporting Information). The durability and stability of the ZMX-M catalyst were also assessed through cycling experiments. ...
The sustainable production of hydrogen utilizing solar energy is a pivotal strategy for reducing reliance on fossil fuels. ZnIn2S4 (ZIS), as a typical metal sulfide semiconductor, has received extensive attention in photocatalysis. Although the introduction of sulfur (S) vacancies in ZIS to enhance photocatalytic hydrogen production by creating defect energy levels has been explored, detailed studies on the control and modulation of S‐vacancies in ZIS are sparce. This study demonstrates that while moderate levels of S‐vacancies can enhance hydrogen evolution, excessive vacancies may hinder the process, underscoring the importance of S‐vacancy modulation. Guided by theoretical calculations, We have designed and synthesized ZIS with modulated S‐vacancies to realize favorable hydrogen adsorption‐free energy and integrated in a Schottky‐heterojunction with MXene co‐catalysts for enhanced hydrogen evolution. The optimized hydrogen evolution performance of ZnIn2S4/MXene (ZMX) reaches 14.82 mmol g⁻¹ h⁻¹ under visible light irradiation, surpassing many reported ZnIn2S4‐based photocatalysts. The enhanced performance is ascribed to widened light absorption and enhanced carrier transportation realized by S‐vacancy modulation and the co‐catalytic effect. Femtosecond ultrafast absorption (fs‐TA) spectra and other in‐situ/ex‐situ characterizations further prove an efficient separation and transfer in an as‐prepared ZMX catalyst. These findings open up new perspectives for designing catalysts with vacancy modulation.
... It is probable that the interaction between Cu and CoSe 2 leads to the shift of WT maximum. The rising edge of the normalized Cu K-edge XANES spectrum of Cu/CoSe 2 /C is close to Cu 2 O, but higher than metallic Cu foil, suggesting the generation of surface oxides in Cu NPs (Fig. 2G) (30,31). And the k 3 -weighted FT-EXAFS spectra from EXAFS in R-space indicate a single Cu-Cu coordination at 2.2 Å, thus providing evidence of the form of metallic Cu (Fig. 2H). ...
As a promising environmental remediation technology, the electro-Fenton (EF) process is mainly limited by the two rate-limiting steps, which are H2O2 generation and activation. The electrocatalytic three-electron oxygen reduction reaction (3e- ORR) can directly activate oxygen to hydroxyl radicals (•OH), which is expected to break through the rate-limiting steps of the EF process. However, limited success has been achieved in the design of 3e- ORR electrocatalysts. Herein, we propose Cu/CoSe2/C with the strong metal-support interactions to enhance the 3e- ORR process, exhibiting remarkable reactivity and stability for •OH generation. Both experiment and DFT calculation results reveal that CoSe2 is conducive to the generation of H2O2. Meanwhile, the metallic Cu can enhance the adsorption strength of *H2O2 intermediates and thus promotes the one-electron reduction to •OH. The Cu/CoSe2/C catalyst exhibits the electron-transfer number close to 3.0 during the ORR process, and exhibits the outstanding •OH generation performance, achieving a higher apparent rate constant (6.0 times faster) toward ciprofloxacin compared with its analogy without the SMSI effect. Our work represents that the SMSI effect endows Cu/CoSe2/C high activity and selectivity for •OH generation, providing a unique perspective for the design of a high-efficiency 3e- ORR catalyst.
... [1,2] Photocatalytic water splitting into hydrogen with particle photocatalysts in a suspension system is a promising technology that can be applied on a large scale. [3,4] The development of photocatalysts with a wide solar spectral response range, [5,6] high charge carrier separation efficiency, [7][8][9] high surface reaction rate, [10] and high stability are the core issues in constructing an efficient photocatalytic hydrogen production system. In recent major breakthroughs, both SrTiO 3 /Al [11] and InGaN/GaN [12] semiconductors with Rh/Cr 2 O 3 and CoOOH as cocatalysts have shown astonishing photocatalytic water splitting activity. ...
... Subsequently, the samples were vacuum dried at 80 • C overnight. To obtain CuPc/ZnIn 2 S 4 with different amounts of CuPc, the amount of CuPc was controlled to be 3 wt%, 5 wt%, 7 wt%, 9 wt%, and 11 wt%, and the samples were labeled x-CuPc/ZIS (x = 3, 5,7,9,11). Furthermore, pristine ZnIn 2 S 4 was prepared without adding CuPc. ...
... Photocatalytic hydrogen evolution by water splitting is considered to be an important strategy to solve the energy and environmental crisis [1][2][3][4][5][6][7][8][9][10] . However, the solar-to-hydrogen (STH) efficiency is quite low due to the unsatisfactory carrier dynamics and thermodynamic performance, which is mainly caused by the easy recombination of photogenerated electrons-holes (e − /h + ), high hydrogen evolution overpotential, and poor conductivity in semiconductor photosystems [11][12][13][14][15][16][17] . ...
... The ΔG H of Ni-O2 is closest to zero (−0.039 eV, even better than Pt, ΔG H(Pt) = −0.22 eV) 9 , theoretically indicating that it is the optimal reaction site. On the whole, the ΔG H of CuNi@O-C = O is relatively smaller, indicating that the chemical coordination of surface atoms was optimized and -O-C = O is more conducive to H adsorption and H 2 desorption. ...
... On the basis of the DFT results, the cocatalytic performance of CuNi will realize substantial improvement by introducing the ester group to form an EDL in terms of increasing the work function and H adsorption/desorption ability, reducing the Fermi level and d-band center 9,13,19,36,45 . Guided by theoretical calculations, we rationally designed a synthesis routine for CuNi@O-C = O (CN@EDL) and applied it as the cocatalyst of CdS. ...
Photocatalytic hydrogen evolution efficiency is limited due to unfavorable carrier dynamics and thermodynamic performance. Here, we propose to introduce electronegative molecules to build an electric double layer (EDL) to generate a polarization field instead of the traditional built-in electric field to improve carrier dynamics, and optimize the thermodynamics by regulating the chemical coordination of surface atoms. Based on theoretical simulation, we designed CuNi@EDL and applied it as the cocatalyst of semiconductor photocatalysts, finally achieved a hydrogen evolution rate of 249.6 mmol h⁻¹ g⁻¹ and remained stable after storing under environmental conditions for more than 300 days. The high H2 yield is mainly due to the perfect work function, Fermi level and Gibbs free energy of hydrogen adsorption, improved light absorption ability, enhanced electron transfer dynamics, decreased HER overpotential and effective carrier transfer channel arose by EDL. Here, our work opens up new perspectives for the design and optimization of photosystems.
... Due to structural mismatch between MOF and LDHs, abundant defects can be introduced around heterointerface. [35] High-resolution TEM (HRTEM) showed an obvious interface between Fe-soc-MOF and NiFe-LDH, proving the formation of heterointerface in MOF/LDH-4h ( Figure S3b and Ni, which is because that numerous organic linkers and solvent guest molecules in MOFs. ...
Precise design of low‐cost, efficient and definite electrocatalysts is the key to sustainable renewable energy. Herein, this work develops a targeted‐anchored and subsequent spontaneous‐redox strategy to synthesize nickel‐iron layered double hydroxide (LDH) nanosheets anchored with monodispersed platinum (Pt) sites (Pt@LDH). Intermediate metal‐organic frameworks (MOF)/LDH heterostructure not only provides numerous confine points to guarantee the stability of Pt sites, but also excites the spontaneous reduction for PtII. Electronic structure, charge transfer ability and reaction kinetics of Pt@LDH can be effectively facilitated by the monodispersed Pt moieties. As a result, the optimized Pt@LDH that with the 5% ultra‐low content Pt exhibits the significant increment in electrochemical water splitting performance in alkaline media, which only afford low overpotentials of 58 mV at 10 mA cm⁻² for hydrogen evolution reaction (HER) and 239 mV at 10 mA cm⁻² for oxygen evolution reaction (OER), respectively. In a real device, Pt@LDH can drive an overall water‐splitting at low cell voltage of 1.49 V at 10 mA cm⁻², which can be superior to most reported similar LDH‐based catalysts. Moreover, the versatility of the method is extended to other MOF precursors and noble metals for the design of ultrathin LDH supported monodispersed noble metal electrocatalysts promoting research interest in material design.
... The fast decay component of τ 1 indicated the trapping of electrons from the conduction band into trap states, and the slow component of τ 2 represented the recombination between electrons and holes in the valence band. [26] The fitting results were τ 1 = 25.6 ps (50%) and τ 2 = 463.4 ps (50%) of g-C 3 N 4 , τ 1 = 13.6 ps (50%) and τ 2 = 317.7 ps (50%) of NGK, and τ 1 = 4.5 ps (66%) and τ 2 = 22.0 ps (34%) of FeSA-NGK, respectively (Table S15, Supporting Information). ...
Single‐atom catalysts (SACs) feature maximum atomic utilization efficiency; however, the loading amount, dispersibility, synthesis cost, and regulation of the electronic structure are factors that need to be considered in water treatment. In this study, kaolinite, a natural layered clay mineral, is applied as the support for g‐C3N4 and single Fe atoms (FeSA‐NGK). The FeSA‐NGK composite exhibits an impressive degradation performance toward the target pollutant (>98% degradation rate in 10 min), and catalytic stability across consecutive runs (90% reactivity maintained after three runs in a fluidized‐bed catalytic unit) under peroxymonosulfate (PMS)/visible light (Vis) synergetic system. The introduction of kaolinite promotes the loading amount of single Fe atoms (2.57 wt.%), which is a 14.2% increase compared to using a bare catalyst without kaolinite, and improved the concentration of N vacancies, thereby optimizing the regulation of the electronic structure of the single Fe atoms. It is discovered that the single Fe atoms successfully occupied five coordinated N atoms and combined with a neighboring N vacancy. Consequently, this regulated the local electronic structure of single Fe atoms, which drives the electrons of N atoms to accumulate on the Fe centers. This study opens an avenue for the design of clay‐based SACs for water purification.
... Energy conversion and storage is critical towards carbonreduction and carbon-neutralization, leading to growing research on energy materials in both academic and industrial levels [1][2][3][4] . The development of catalysts has thus become one of the major research fields [5][6][7][8] , as catalytic process is the cornerstone for successful implementation of many applications, such as electrocatalysis [9][10][11][12] , photocatalysis [13][14][15][16][17][18][19] , batteries [3,5,[20][21][22] , etc., and thus offers noteworthy solutions to future energy conversion and storage technologies [10,11,[23][24][25] . Therefore, the development of efficient catalysts for catalysis, such as hydrogen evolution reaction(HER) [9,12,[26][27][28] , oxygen evolution reaction(OER) [28][29][30] , oxygen reduction reaction(ORR) [9,[31][32][33][34][35][36][37] , CO2 reduction reaction(CO2 RR) [7,[38][39][40] , nitrogen reduction reaction (NRR) [41][42][43] and other catalytic reactions [44][45][46][47][48][49] has attracted much interest and has boosted intensive investigation in past decades. ...
... In addition to metals/alloys and metal oxides, other metalbased supports have been widely used to support single-atoms, such as metal sulfides, metal selenides, etc. Metal sulfides, which are mostly presented as 2D materials, are considered as ideal non-carbon substrates to anchor single metal atoms by forming M-Sx bonds [86] . Su et al. [14] reported a metal doping strategy to stabilizing single atoms and thus addressed the In addition to sulfides, selenides are also potential substrates for anchoring single-metal atoms. It has been reported that single-metal atoms modified CoSe2 exhibited superior OER activity than pristine CoSe2, owing to the strong metal-support interactions by forming M-Se bonds [27] . ...
Clean energy innovation has triggered the development of single-atom catalysts(SACs) due to their excellent catalytic activity, high tunability and low cost. The success of SACs for many catalytic reactions has opened a new field where the fundamentals of catalytic property-structure relationship at atomic level await exploration, and thus raises challenges for structural characterization. Among the characterization techniques for SACs, aberration-corrected transmission electron microscopy(TEM) has become an essential tool for direct visualization of single atoms. In this review, we briefly summarize recent studies on SACs using advanced TEM. We first introduce TEM methods, which are particularly important for SACs characterization, and then discuss the applications of advanced TEM for SAC characterization, where not only atomic dispersion of single atoms can be studied, but also the distribution of elements and the valence state with local coordination can be resolved. We further extend our review towards in-situ TEM, which has increasing importance for the fundamental understanding of catalytic mechanism. Perspectives of TEM for SACs are finally discussed.
... Meanwhile, Pt can also be worked as a prominent cocatalyst to boost the PC HER activity of photocatalysts, such as g-C 3 N 4 . [3] Low-cost g-C 3 N 4 is a popular 2D material for PC water splitting due to its visible light response. [4] However, the efficiency of the PC water splitting of g-C 3 N 4 is limited by the high charge recombination rate and sluggish redox kinetics. ...
Sustainable and highly efficient non‐noble metal catalysts could facilitate the realization of closed‐loop and carbon‐neutral hydrogen (H2) economy via low‐cost electrocatalytic (EC) or photocatalytic (PC) H2 evolution reaction (HER) from water. Herein, molybdenum carbide (MoC) quantum dots onto N‐doped porous carbon are in situ synthesized and immobilized, resulting in a bifunctional catalyst MoC@NC. Density functional theory calculation suggests that the targeted catalyst has a suitable Gibbs free‐energy (ΔGH*) for the adsorption of atomic hydrogen, which is beneficial to both EC and PC HERs. For EC HER, the as‐prepared MoC@NC catalyst delivers a low overpotential of 160 mV at −10 mA cm⁻² and a remarkable H2 evolution rate in alkaline electrolytes. For PC HER, MoC@NC couple with 2D graphitic carbon nitride (g‐C3N4), which significantly reduces the PC HER energy barrier and enhances the separation efficiency of photogenerated carriers, and consequently, achieves an outstanding photocatalytic H2 evolution rate of 1709 µmol h⁻¹ g⁻¹, which is 213‐fold of that of pure g‐C3N4. This work paves a new avenue for developing sustainable non‐noble metal catalysts for both EC and PC HERs.
... Up to now, multiple strategies have been explored to solve the sluggish charge transfer kinetics of those photocatalysis, for instance, cocatalysts loading, metal/nonmetal doping, heterojunction constructing, morphology controlling, hierarchical nanostructure fabricating, and the like [17][18][19][20][21]. Integrating the noble metal cocatalyst, such as Ag, Au, and Pt, to a semiconductor is a conventional path to improve the photocatalytic capability by forming the Schottky junction or Ohmic contains [22]. ...
The well-designed interface plays a key role in enhancing the charge transfer kinetics. In this work, a three-dimensional CoSe2/Cd0.8Zn0.2S Schottky junction was successfully prepared using zeolitic imidazolate framework-67 (ZIF-67) as precursor material by in-situ chemistry synthetic strategies to improve the charge transfer kinetics. The photocatalytic H2 generation rate of 3.2%-CoSe2/Cd0.8Zn0.2S is 80 times higher than pristine Cd0.8Zn0.2S. The systematic characterization (XPS, TRPL, EPR, etc.) and DFT results show the improvement of photocatalytic performance derives from the formation of Schottky junction between CoSe2 and Cd0.8Zn0.2S. The well-designed and tight interface can facilitate electrons transfer from Cd0.8Zn0.2S to CoSe2, and Schottky barrier can suppress the electrons flow back to Cd0.8Zn0.2S, resulting in the high separation of charge carriers. On the other hand, the noble metal-free CoSe2 with larger specific surface area function as the electron acceptors and active sites for reducing H⁺ to H2 efficiently, thus in favor of obtaining the enhanced H2 generation performance. Combining the three-dimensional structure with Schottky junction, this work provides an effective strategy to prepare photocatalysts.
