A novel photothermal-assisted FeNi2S4@Mn0.3C0.7S S-scheme heterojunction for enhanced photo-catalytic hydrogen evolution

In addition to the intrinsic driving force of photocatalysis, the external thermal field from the photothermal effect can provide additional energy to the photo-catalytic system to improve the photo-catalytic hydrogen-evolution (PHE) efficiency. Herein, based on the results of density functional theory, we designed and constructed a hollow core-shell FeNi2S4@Mn0.3Cd0.7S (NFS@MCS) S-scheme heterojunction with a photothermal effect, thereby realising a significant enhancement of the PHE performance due to the thermal effect, S-scheme heterojunction and hollow core-shell morphology. As a light collector and heat source, the hollow NFS could absorb and convert photons into heat, resulting in the increased local temperature of photocatalyst particles. Moreover, the S-scheme charge path at the interface not only improved the carrier separation efficiency but also retained a higher redox potential. All these are favourable to increase the PHE activity. The PHE tests show that 0.5 %-NFS@MCS exhibits the highest PHE rate of 17.11 mmol·g-1·h-1, 7.7 times that of MCS. Moreover, through a combination of theoretical calculation and experimental evidence, the PHE mechanism of the NFS@MCS system is discussed and clarified in-depth.

Advanced photocatalytic materials based degradation of micropollutants and their use in hydrogen production - a review

The use of pharmaceuticals, dyes, and pesticides in modern healthcare and agriculture, along with expanding industrialization, heavily contaminates aquatic environments. This leads to severe carcinogenic implications and critical health issues in living organisms. The photocatalytic methods provide an eco-friendly solution to mitigate the energy crisis and environmental pollution. Sunlight-driven photocatalytic wastewater treatment contributes to hydrogen production and valuable product generation. The removal of contaminants from wastewater through photocatalysis is a highly efficient method for enhancing the ecosystem and plays a crucial role in the dual-functional photocatalysis process. In this review, a wide range of catalysts are discussed, including heterojunction photocatalysts and various hybrid semiconductor photocatalysts like metal oxides, semiconductor adsorbents, and dual semiconductor photocatalysts, which are crucial in this dual function of degradation and green fuel production. The effects of micropollutants in the ecosystem, degradation efficacy of multi-component photocatalysts such as single-component, two-component, three-component, and four-component photocatalysts were discussed. Dual-functional photocatalysis stands out as an energy-efficient and cost-effective method. We have explored the challenges and difficulties associated with dual-functional photocatalysts. Multicomponent photocatalysts demonstrate superior efficiency in degrading pollutants and producing hydrogen compared to their single-component counterparts. Dual-functional photocatalysts, incorporating TiO2, g-C3N4, CeO2, metal organic frameworks (MOFs), layered double hydroxides (LDHs), and carbon quantum dots (CQDs)-based composites, exhibit remarkable performance. The future of synergistic photocatalysis envisions large-scale production facilitate integrating advanced 2D and 3D semiconductor photocatalysts, presenting a promising avenue for sustainable and efficient pollutant degradation and hydrogen production from environmental remediation technologies.

Construction of a heterojunction with fast charge transport channels for photocatalytic hydrogen evolution via a synergistic strategy of Co-doping and crystal plane modulation

Carrier spatial separation efficiency and active electron density are the key factors affecting photocatalytic hydrogen evolution activity. Heterojunction catalysts with fast charge separation and directed electron transport systems were successfully prepared by a synergistic modification strategy of transition metal (Co) doping and crystal plane modulation. The optimized electronic structure and enhanced reaction kinetics enabled unidirectional electron transfer. Photocatalytic results show that CdS(002)/Co-C₃N₄ exhibits remarkable hydrogen evolution activity (991.2 μmol h^-1 g^-1) in the absence of a co-catalyst, which is 37.0 and 3.4 times higher than that of C₃N₄ (26.8 μmol h^-1 g^-1) and Co-C₃N₄ (294.6 μmol h^-1 g^-1), respectively. Density functional theory (DFT) calculations indicate that the enhanced catalytic activity of CdS(002)/Co-C₃N₄ is attributed to the reduced electron-hole recombination rate and the increased electron density at the active site. This work provides a new idea for the design of photocatalysts with directed charge transport channels from the perspective of re-optimizing heterojunctions.

Bifunctional thioacetamide-mediated synthesis of few-layered MoOSx nanosheet-modified CdS hollowspheres for efficient photocatalytic H2 production

Constructing efficient cocatalyst-modified hollow-structured photocatalysts holds great potential in the photocatalytic H2 evolution field. Regrettably, it still remains a formidable challenge to develop cost-effective cocatalysts and explore simple synthetic methods...