Yanzhao Zhang's research while affiliated with The University of Queensland and other places

Water splitting provides clean hydrogen via different technologies such as alkaline water electrolysis, proton exchange membrane electrolyzers, solid oxide electrolysis cells, and photoelectrolysis, each with advantages and challenges. The focus on alkaline water electrolysis highlights its maturity compared to emerging methods. Non-noble metal catalysts offer increased stability, low cost and operational lifespan. Challenges such as low current density, gas crossover, corrosive electrolytes, and limited efficiency are still to be addressed. These advanced electrocatalysts are summarized for alkaline oxygen and hydrogen evolution reactions. Meanwhile, different factors including product gas bubble management, operation conditions, separator and electrolyte affecting the performance were concluded and discussed. For the promising approach, seawater splitting is still far from large-scale application. Salinity, pH fluctuations, and complex composition are significant obstacles. The review underscores the need for improvements in electrocatalysts to enhance the efficiency, stability, and practicality of water splitting for hydrogen production, ultimately contributing to the growth of the clean hydrogen market and supporting the transition to sustainable energy systems.

Photogenerated charge localization on material surfaces significantly affects photocatalytic performance, especially for multi‐electron CO 2 reduction. Dual single atom (DSA) catalysts with flexibly designed reactive sites have received significant research attention for CO 2 photoreduction. However, the charge transfer mechanism in DSA catalysts remains poorly understood. Here we report for the first time a reversed electron transfer mechanism on Au and Co DSA catalysts. In situ characterizations confirm that for CdS nanoparticles (NPs) loaded with Co or Au single atoms, photogenerated eletrons are localized around the single atom of Co or Au. In DSA catalysts however electrons are delocalized from Au and accumulate around Co atoms. Importantly, combined advanced spectroscopic findings and theoretical computation evidence that this reversed electron transfer in Au/Co DSA boosts charge redistribution and activation of CO 2 molecules, leading to highly significantly increased photocatalytic CO 2 reduction, for example, Au/Co DSA loaded CdS exhibits, respectively, ca . 2800% and 700% greater yields for CO and CH 4 compared with that for CdS alone. Reversed electron transfer in DSA can be used for practical design for charge redistribution and to boost photoreduction of CO 2 . Findings will be of benefit to researchers and manufacturers in DSA loaded catalysts for generation of solar fuels. This article is protected by copyright. All rights reserved

Electrocatalytic water splitting is promising for green hydrogen production. However, the high energy barrier and sluggish kinetics of the anodic oxygen evolution reaction (OER) lead to high energy consumption, burdening the large-scale industrial application. Hybrid water electrolysis using two-dimensional (2D) electrocatalysts is considered as a promising way to reduce the cost of electrocatalytic green hydrogen production. It reduces the electricity cost by earth-abundant electrode materials, alternative energy-saving reactions, and novel electrolyzers. In this review, we systematically analyze the promising hybrid water electrocatalysis by 2D electrocatalysts. The advantages and status quo, as well as important future directions and feasibilities of this emerging field, are carefully discussed. We reveal that developing well-matched alternative reactions and stable reactors/devices are two critical factors for efficient hybrid water electrolysis. To improve the practical and economic feasibility of hybrid water electrocatalysis, it is promising to integrate tandem reactions with hybrid water electrocatalysis and advanced electrolyzers to achieve higher efficiency and selectivity. We conclude that developing stable 2D electrocatalysts, finding matched reactions, and efficient devices are the core for advancing hybrid water electrocatalysis.

Photocatalytic performance can be optimized via introduction of reactive sites. However, it is practically difficult to engineer these on specific photocatalyst surfaces, because of limited understanding of atomic‐level structure‐activity. Here we report a facile sonication‐assisted chemical reduction for specific facets regulation via oxygen deprivation on Bi‐based photocatalysts. The modified Bi2MoO6 nanosheets exhibit 61.5 and 12.4 μmol g⁻¹ for CO and CH4 production respectively, ≈3 times greater than for pristine catalyst, together with excellent stability/reproducibility of ≈20 h. By combining advanced characterizations and simulation, we confirm the reaction mechanism on surface‐regulated photocatalysts, namely, induced defects on highly‐active surface accelerate charge separation/transfer and lower the energy barrier for surface CO2 adsorption/activation/reduction. Promisingly, this method appears generalizable to a wider range of materials.

Photocatalytic performance can be optimized via introduction of reactive sites. However, it is practically difficult to engineer these on specific photocatalyst surfaces, because of limited understanding of atomic‐level structure‐activity. Here we report a facile sonication‐assisted chemical reduction for specific facets regulation via oxygen deprivation on Bi‐based photocatalysts. The modified Bi2MoO6 nanosheets exhibit 61.5 and 12.4 μmol g–1 for CO and CH4 production respectively, ~3 times greater than for pristine catalyst, together with excellent stability/reproducibility of ~20 h. By combining advanced characterizations and simulation, we confirm the reaction mechanism on surface‐regulated photocatalysts, namely, induced defects on highly‐active surface accelerate charge separation/transfer and lower the energy barrier for surface CO2 adsorption/activation/reduction. Promisingly, this method appears generalizable to a wider range of materials.

The aggravating extreme climate changes and natural disasters stimulate the exploration of low‐carbon/zero‐carbon alternatives to traditional carbon‐based fossil fuels. Solar‐to‐hydrogen (STH) transformation is considered as appealing route to convert renewable solar energy into carbon‐free hydrogen. Restricted by the low efficiency and high cost of noble metal cocatalysts, high‐performance and cost‐effective photocatalysts are required to realize the realistic STH transformation. Herein, the 2D FePS3 (FPS) nanosheets anchored with TiO2 nanoparticles (TiO2/FePS3) are synthesized and tested for the photocatalytic hydrogen evolution reaction. With the integration of FPS, the photocatalytic H2‐evolution rate on TiO2/FePS3 is radically increased by ≈1686%, much faster than that of TiO2 alone. The origin of the greatly raised activity is revealed by theoretical calculations and various advanced characterizations, such as transient‐state photoluminescence spectroscopy/surface photovoltage spectroscopy, in situ atomic force microscopy combined with Kelvin probe force microscopy (AFM‐KPFM), in situ X‐ray photoelectron spectroscopy (XPS), and synchrotron‐based X‐ray absorption near edge structure. Especially, the in situ AFM‐KPFM and in situ XPS together confirm the electron transport pathway in TiO2/FePS3 with light illumination, unveiling the efficient separation/transfer of charge carrier in TiO2/FePS3 step‐scheme heterojunction. This work sheds light on designing and fabricating novel 2D material‐based S‐scheme heterojunctions in photocatalysis.

The depletion of traditional fossil fuels and related environmental issues have increased the demand for clean and sustainable energy resources to achieve carbon neutrality. Active, robust and cheap photocatalysts are required for large-scale photocatalytic H2 evolution reaction (p-HER), which transforms solar energy into chemical energy. Here we report the decoration of Ni-imidazole framework (NiIm) with CdS nanorods for p-HER. The p-HER rate of CdS/NiIm hybrid sharply increased by about 14.23 times to 21,712 µmol h⁻¹ g⁻¹ when compared with that of CdS alone. Physicochemical characterizations and theoretical calculations reveal strong interactions at the CdS/NiIm interface and the presence of numerous Ni-N4 active sites on NiIm leading to the significant performance enhancement. This work demonstrates that NiIm acts as an affordable and abundant co-catalyst that remarkably enhances the p-HER, and enlightens the further development in the design and preparation of metal-organic framework-based materials for various applications in photocatalysis and related subjects.

Artificial photosynthesis can provide valuable fuels and positively impact greenhouse effects, via transforming carbon dioxide (CO2) and water (H2O) into hydrocarbons using semiconductor‐based photocatalysts. However, the inefficient charge‐carrier dissociation and transportation as well as the lack of surface active sites are two major drawbacks to boosting their activity and selectivity in photocatalytic CO2 reduction. Recently, ReS2 has received tremendous attention in photocatalysis area owing to its intriguing physicochemical properties. Nevertheless, the application of ReS2 in photocatalytic CO2 reduction is scarcely covered. In this study, we report a heterojunction formed between ReS2 nanosheets and CdS nanoparticles, achieving an apparently‐raised CO production of 7.1 μmol g‐1 and high selectivity of 93.4%. The as‐prepared ReS2/CdS heterojunction exhibits the strengthened visible‐light absorption, high‐efficiency electron‐hole pairs separation/transfer and increased adsorption/activation/reduction of CO2 on in situ created sulphur vacancies of ReS2, thus all favouring CO2 photoreduction. These are corroborated by advanced characterization techniques, e.g., synchrotron‐based X‐ray absorption near‐edge structure, and density functional theory based computations. Our findings will be of a broad interest in practical design and fabrication of surface active sites and semiconductor heterojunctions for applications in catalysis, electronics and optoelectronics. This article is protected by copyright. All rights reserved.

Single-atom photocatalysts have demonstrated an enormous potential in producing value-added chemicals and/or fuels using sustainable and clean solar light to replace fossil fuels causing global energy and environmental issues. These photocatalysts not only exhibit outstanding activities, selectivity, and stabilities due to their distinct electronic structures and unsaturated coordination centers but also tremendously reduce the consumption of catalytic metals owing to the atomic dispersion of catalytic species. Besides, the single-atom active sites facilitate the elucidation of reaction mechanisms and understanding of the structure-performance relationships. Presently, apart from the well-known reactions (H2 production, N2 fixation, and CO2 conversion), various novel reactions are successfully catalyzed by single-atom photocatalysts possessing high efficiency, selectivity, and stability. In this contribution, we summarize and discuss the design and fabrication of single-atom photocatalysts for three different kinds of emerging reactions (i.e., reduction reactions, oxidation reactions, as well as redox reactions) to generate desirable chemicals and/or fuels. The relationships between the composition/structure of single-atom photocatalysts and their activity/selectivity/stability are explained in detail. Additionally, the insightful reaction mechanisms of single-atom photocatalysts are also introduced. Finally, we propose the possible opportunities in this area for the design and fabrication of brand-new high-performance single-atom photocatalysts.