Xuefeng He

University of Leeds · School of Chemistry

The ability to control crystal nucleation through the simple addition of a nucleating agent (nucleant) is desirable for a huge range of applications. However, effective nucleating agents are known for only a small number of systems, and many questions remain about the mechanisms by which they operate. Here, we explore the features that make an effe...

To realize online noncontact detection of the degree of chemical corrosion of stone cultural relics, we developed a reflective fiber-optic sensor and a theoretical model was established. The sensor comprised incident and receiving coaxial fibers located in the middle and inner and outer layers of the coaxial fiber, respectively. We investigated the...

Dark fermentation (DF) with notorious algal blooms (ABs) is a promising approach to simultaneously resolve water pollution and energy shortage with extra benefit of carbon neutralization, but it is challenging due to inefficient biomass harvesting and fermentation. To conquer these problems, a strategy using chitosan as dual-functional mediators wa...

Tetracyclines are refractory pollutants that cause persistent harm to the environment and human health. Therefore, it is urgently necessary to develop methods to promote the efficient degradation and conversion of tetracyclines in wastewater. This report proposes a photobiocatalytic synergistic system involving the coupling of GeO2/Zn-doped phospho...

The use of amorphous calcium carbonate (ACC) as a precursor phase affords organisms with outstanding control over the formation of calcite and aragonite biominerals. Essential to this strategy is that the ACC is maintained within confined volumes in the absence of bulk water. This ensures that the ACC undergoes a pseudomorphic transformation and th...

This study proposed a mild chlorination-sulfonation approach to synthesize magnetic carbon acid bearing with catalytic SO3H and adsorption Cl bifunctional sites on polydopamine coating. The catalysts exerted good textural structure and surface chemical properties (i.e., porosity, high specific surface area of > 70 m²/g, high catalytic activity with...

Globally eruptive harmful algal blooms (HABs) have caused numerous negative effects on aquatic ecosystem and human health. Conversion of HABs into biohythane via dark fermentation (DF) is a promising approach to simultaneously cope with environmental and energy issues, but low HABs harvesting efficiency and biohythane productivity severely hinder i...

Solar driven interfacial evaporation has caught the eyes of global researchers in the past few years due to its outstanding vapor generation ability by using clean solar energy. Extensive investigations have been carried out to explore solar absorber/receiver materials for efficient photothermal conversion and heat concentration at the water-air in...

X-ray scattering techniques provide a powerful means of characterizing the formation of nanoparticles in solution. Coupling these techniques to segmented-flow microfluidic devices that offer well-defined environments gives access to in situ time-resolved analysis, excellent reproducibility, and eliminates potential radiation damage. However, analys...

Localized fluid manipulation in microfluidic device is a key operation to various on-chip analytical/synthetic applications. In this work, we demonstrated the localized fluid actuation in microchannels by the infrared laser-induced evaporation–condensation-coalescence photothermal phase change process. Visualized experiments were carried out to inv...

In the present study, we present a 3D oriented CuS/Cu2O/Cu nanowire photocathode grown on the copper foam. This newly-developed photocathode can effectively enhance the separation of electron-hole pairs and anti-photocorrosion as a result of the nanowire structure and bandgap gradient. In the meantime, it can provide more active sites and promote t...

Microfluidic devices for sample crystallization separation plays crucially important role in various on-chip analytical and testing scenes. Evaporation-based microfluidic crystallization technology is one of the most important methods for on-chip sample enrichment and crystallization separation. However, the solvent evaporation process in closed ch...

The ultra-precise manipulation of the droplets at the microscale is a promising paradigm for broad implications in reagent transport and element analysis but the existing strategies still suffer from the cross-contamination or the miscellaneous auxiliaries. Inspired by the levitation, we develop a method for excellently manipulating levitated femto...

Solar-driven electrochemical CO2 reduction to fuels has considerable potential to satisfy future renewable energy needs and mitigate CO2 emissions, but current approaches face significant challenges, such as poor selectivity and large overpotential for the catalytic reactions. Here we present a hybrid microbial-photoelectrochemical system that sele...

In this work, a photocatalytic fuel cell (PFC) with membrane electrode assembly (MEA) structure was designed for simultaneous organic compounds degradation and electricity generation. For the photoanode, the TiO2 with the quantum-dot sensitization by CdS-ZnS was used to broaden the absorption spectrum to visible light. For the cathode, an air-breat...

In this study, a novel ternary hybrid CdS/SiO2/TiO2 film was proposed as the phonoanode for the photocatalytic fuel cell. The samples were characterized by X-ray diffraction, scanning electron microscopy and UV–vis absorption. The photoelectrochemical activity of the ternary hybrid electrode was characterized by the photocurrent-time transient resp...

With the promising potential in non-contact fluid manipulation, the photothermally induced phase change along with the interfacial behaviors have been frequently applied in various microfluidic devices. The property of the working fluid greatly affects the photothermal conversion and thus phase change behaviors. For this reason, the IR laser induce...

The study on cells in vitro usually encounters the signals with oscillatory or periodic temporal profiles, which requires the pulsating flow control. Aiming at this target, a novel approach to generate the pulsating waveform of fluid flow by the photothermally induced phase change in the microchannel with the sawtooth-shaped baffles was developed i...

In this work, the control of the droplet generation by a focused infrared (IR) laser with a wavelength of 1550 nm was studied, in which the liquid water and the oil with the surfactant of Span 80 were employed as the disperse and continuous phases, respectively. The characteristics of the droplet generation controlled by the laser was explored unde...

In this work, a membrane electrode assembled photoelectrochemical cell (PEC) is developed for the electricity generation by degrading the organic compounds. The photocatalyst is prepared by the incorporation of mesoporous silica SBA-15 into TiO2 and the photosensitization of CdS-ZnS to enhance the photoanode performance, while the cathode employs t...

The photothermal effect of a laser can be advantageously used to manipulate the droplets coalescence, which usually encounters the coalescence between two droplets with different temperatures. In this study, the dynamic behavior of the coalescence between two droplets with different temperatures in oil is simulated using the volume of fluid (VOF) m...

In present study, a micro membrane-less photoelectrochemical cell (μML-PEC) is developed for simultaneous hydrogen and electricity productions in the presence of methanol, in which the photoanode of a TiO2 film is consisted of a compact layer at the bottom and a porous layer on the top. The experimental results indicate the PEC miniaturization, and...

In this study, a novel mesoporous CdS/TiO2[email protected]/* */ paper composite membrane was developed to enhance the visible-light responsive CO2 photoreduction in an optofluidic membrane microreactor. The microscopic morphological and pore volume characterizations indicated that the incorporation of the mesoporous SBA-15 into the membrane develo...

The development of highly efficient photocatalytic reactor is of importance to improve the performance of the photocatalytic reduction of CO2. In this work, an optofluidic planar microreactor is designed and fabricated for the photocatalytic reduction of CO2 with liquid water in alkaline environment. Such design offers several advantages of large s...

In this study, a membraneless, monolithic micro photocatalytic fuel cell with an air-breathing cathode was developed for simultaneous wastewater treatment and electricity generation. In this newly-developed micro photocatalytic fuel cell, the photoanode and cathode were arranged with a shoulder-to-shoulder design, forming two planar electrodes. Suc...

Conventional photocatalytic ozonation usually suffers from the mass transport issue associated with low specific surface area and gas/liquid interface and liquid film. To address this issue, a new membrane microreactor based on optofluidics was developed for wastewater treatment by the photocatalytic ozonation in this work. The key component of the...

In this paper, the IR laser photothermally induced phase change characteristics in the microchannels with different wettabilities were studied using visual experiments. The hydrophobic microchannel was obtained by the hydrophobic nature of the PDMS material while the hydrophilic microchannels were obtained by the inert gas plasma surface treatments...

The photothermal effect induced phase change is an important phenomenon in optofluidics. In this work, therefore, the characteristics of the phase change in microchannels with different depths induced by a 1550 nm infrared laser under both low and high laser powers was visually studied. It was revealed that at low laser power, the liquid body could...

Photocatalytic reduction of CO2 is a promising technology to capture CO2 and convert it into solar fuels simultaneously. However, current photoreactors usually face the problems of low specific surface area, non-uniform light distribution and poor photon transfer. To address these issues, a novel optofluidic membrane microreactor with high surface-...

The dynamic behavior of the moving liquid column coalescing with a sessile droplet in triangular microchannels is numerically investigated by using coupled volume of fluid with level set interface tracking method implemented in ANSYS Fluent 14.5 in conjunction with the continuum surface force model. It is found that for both hydrophobic and hydroph...

In this work, the characteristics of the meniscus evaporation from a microchannel were studied, which was induced by the photothermal effect of the infrared laser with the wavelength of 1550 nm. The evaporation rate and mass transfer coefficient at the interface were determined by the proposed image process technique coupled with an infrared camera...

In this study, the dynamic behavior of the moving liquid column coalescing with a sessile droplet in a hydrophobic microchannel under pressure driven flow conditions is numerically investigated using coupled Volume of Fluid with Level Set (CLSVOF) interface tracking method implemented in ANSYS-Fluent 14.5 in conjunction with the continuum surface f...

The coalescence between liquid flow and droplets is usually encountered in liquid filling or some new microdevices; a deep understanding of its underlying mechanism is required. In this work, therefore, the dynamic behaviors of this atypical phenomenon in microchannels were visually investigated with droplets generated by photothermally induced eva...

In this work, the condensation behaviors of distilled water actuated by photothermal effect of the infrared laser with the wavelength of 1550 nm in a microchannel were investigated through the visualization method and image processing technique. The impacts of the laser power and the laser spot position on the interface movement and slug formation...