Utilizing 2D materials to enhance H2 generation efficiency via photocatalytic reforming industrial and solid waste.

Sustainable valorization of industrial and solid wastes by utilizing them as feedstock to generate H2 via the photocatalytic reforming (PR) process holds great promise. It can also be an effective method to treat solid waste that otherwise would require tedious and expensive processes. This approach has the potential to offer energy solutions and form value-added chemicals. In this direction, developing photocatalysts and tuning their properties play an essential role in advancing the H2 generation efficiency. This Review article explores the application of 2D photocatalysts to generate H2 via PR of industrial waste (H2S) and solid waste, such as plastic and biomass. Despite having favorable optoelectronic properties, 2D photocatalysts are not widely employed for the PR process. The latest progress in employing 2D photocatalysts to realize efficient H2 evolution from biomass, plastic, and industrial waste such as H2S is detailed in this Review. A correlation between the properties of 2D photocatalysts with H2 evolution rate is discussed. We also emphasize understanding the mechanism involved in the PR process and the importance of 2D photocatalysts design. Such rational insight aids in further enhancing the H2 generation efficiency by effectively using solid/industrial waste as a feedstock.

Efficient Electron Transfer across a ZnO-MoS2 -Reduced Graphene Oxide Heterojunction for Enhanced Sunlight-Driven Photocatalytic Hydrogen Evolution.

The development of noble metal-free catalysts for hydrogen evolution is required for energy applications. In this regard, ternary heterojunction nanocomposites consisting of ZnO nanoparticles anchored on MoS2 -RGO (RGO=reduced graphene oxide) nanosheets as heterogeneous catalysts show highly efficient photocatalytic H2 evolution. In the photocatalytic process, the catalyst dispersed in an electrolytic solution (S2- and SO32- ions) exhibits an enhanced rate of H2 evolution, and optimization experiments reveal that ZnO with 4.0 wt % of MoS2 -RGO nanosheets gives the highest photocatalytic H2 production of 28.616 mmol h-1 gcat-1 under sunlight irradiation; approximately 56 times higher than that on bare ZnO and several times higher than those of other ternary photocatalysts. The superior catalytic activity can be attributed to the in situ generation of ZnS, which leads to improved interfacial charge transfer to the MoS2 cocatalyst and RGO, which has plenty of active sites available for photocatalytic reactions. Recycling experiments also proved the stability of the optimized photocatalyst. In addition, the ternary nanocomposite displayed multifunctional properties for hydrogen evolution activity under electrocatalytic and photoelectrocatalytic conditions owing to the high electrode-electrolyte contact area. Thus, the present work provides very useful insights for the development of inexpensive, multifunctional catalysts without noble metal loading to achieve a high rate of H2 generation.