Solar-driven hydrogen production can alleviate ever-growing energy crisis, but developing affordable and efficient photocatalysts is challenging. We here report a noble-metal-free WO3@ZnIn2S4 S-scheme heterojunction photocatalyst with ZnIn2S4 nanosheets vertically growing...

H2-production and electron-transfer mechanism of noble-metal-free WO3@ZnIn2S4 S-scheme heterojunction photocatalyst

Constructing interfacial active sites in Ru/g-C3N4−x photocatalyst for boosting H2 evolution coupled with selective benzyl-alcohol oxidation

Metal-sulfide nanostructures have piqued the interest of researchers for decades due to their intriguing optoelectronic properties. Indeed, significant advances and improvements have been made in various fundamental aspects for cutting-edge applications, such as water splitting and hydrogen production. Furthermore, rising demand for low-dimensional materials due to lower material consumption and improved performance due to quantum size effects has spurred research on semiconducting metal sulfides. Consequently, size-controllable nanostructures with diverse morphologies have been fabricated and studied for potential applications. However, the photocatalytic hydrogen evolution rate is still limited mainly by fast recombination rate, poor solar energy utilization and lack of surface-active sites for H2 reduction. This review will highlight particularly recent findings in metal-sulfide-based photocatalysts for hydrogen evolution reactions, considering the swift development and excellent research in this field. Following a brief overview of fundamental properties, we will explore state-of-the-art strategies for enhancing H2 generation efficiencies over the pristine, heterostructured and co-catalayzed metal-sulfide photocatalysts.

https://www.mdpi.com/2073-4344/12/11/1316/pdf?version=1667386496

Metal Sulfide Photocatalysts for Hydrogen Generation: A Review of Recent Advances

The increasingly massive consumption of plastics is becoming a global pollution disaster, with serious environmental and economic problems. Here we report an efficient and sustainable strategy for the visible-light-driven upcycling of various plastic wastes into high-value-added formic acid. We firstly design and fabricate a self-assembly Z-scheme heterostructure of V-substituted phosphomolybdic acid clusters/g-C3N4 nanosheets (VPOM/CNNS). The Z-scheme charge transfer process is unambiguously elucidated by transient absorption spectra and electron spin resonance studies, which endow VPOM/CNNS heterostructure with efficient charge separation and strong redox potentials. Consequently, VPOM/CNNS heterostructure displays a superior photocatalytic performance toward upcycling of various plastics. The optimal VPOM/CNNS composite exhibits a remarkable formic acid production rate of 24.66 μmol h−1 g−1 for upcycling of polyethylene, which is 262-fold higher than that of pristine CNNS. This work highlights the potential of Z-scheme heterojunction as an unusual tool for the photo-driven upcycling of plastic waste. 

Solar energy-driven upcycling of plastic waste on direct Z-scheme heterostructure of V-substituted phosphomolybdic acid/g-C3N4 nanosheets

Dual-channels separated mechanism of photo-generated charges over semiconductor photocatalyst for hydrogen evolution: Interfacial charge transfer and transport dynamics insight

Efficient aromatic alcohol oxidation with simultaneous H2 evolution under aqueous conditions is achieved in a polyoxometalate (POM)-incorporated ZnIn2S4 dual-functional photocatalytic system. The synergy between HPM and ZIS contributes to the formation of a Z-type heterojunction structure and thus enhances redox capacity. Moreover, the sub-nanometer size of POM clusters endows molecular-level interfacial contact, which acts as an "electron bridge" ensuring faster interfacial charge transfer kinetics. Therefore, an impressive nearly 100% yield of benzaldehyde and 10.6 mmol·g−1·h−1 H2-evolution rate are observed for POM/ZIS nanocomposites even under an anaerobic atmosphere with water as the solvent. This is the first application of POM-based materials in the anaerobic oxidation of benzyl alcohol with concomitant H2 production. This study expands the possibilities for designing multifunctional POM-based photocatalysts for economic and ecological photoredox applications. 

POM-incorporated ZnIn2S4 Z-scheme Dual-functional Photocatalysts for Cooperative Benzyl Alcohol Oxidation and H2 Evolution in Aqueous Solution

Although Schottky barriers at the interface of metal/semiconductor help electron/hole separation in photocatalysis, they also limit the migration of electrons across the interface. Herein, we tune Schottky barriers over Ni/S vacancy-rich Mn0.3Cd0.7S (Ni/MCS-s) composites prepared by self-assembly and photochemical method. The Ni/MCS-s heterostructures exhibits superior hydrogen production activity up to 164.1 mmol/h/g in simulated seawater (3.5 wt% NaCl), which is 68 and 5 times higher than MCS-s and 1 wt% Pt/MCS-s, respectively. The apparent quantum yield reached 60.4% at 420 nm. The excellent photocatalytic performance of Ni/MCS-s results from the coupling of plasmonic Ni and S vacancies, which can effectively lower Schottky barrier and enhance hot electrons across the interface for photocatalytic process. Moreover, the Ni layer effectively prevents the catalyst from being corroded in seawater. This work provides a feasible strategy for designing efficient photocatalysts for solar energy conversion in seawater. 

Renyou Zeng

Papers

POM-incorporated ZnIn2S4 Z-scheme Dual-functional Photocatalysts for Cooperative Benzyl Alcohol Oxidation and H2 Evolution in Aqueous Solution

Schottky barrier tuning via surface plasmon and vacancies for enhanced photocatalytic H2 evolution in seawater

Tailored boron phosphate monolithic foam with multimodal hierarchically porous structure and its applications