Enhanced photocatalytic H₂-evolution by immobilizing CdS nanocrystals on ultrathin Co_0.85Se/RGO–PEI nanosheets

Abstract

We herein report a novel noble-metal-free photocatalytic H 2 -production system by immobilizing CdS nanocrystals on ultrathin Co 0.85 Se/graphene nanosheets. The well-designed composite material was prepared by a simple solvothermal method and achieved a dramatically enhanced H 2 -evolution performance when compared with other bulk counterparts. Under optimal conditions, the H 2 -evolution efficiency can reach up to 17.60 mmol mg À1 h À1 after 10 h of LED visible light irradiation, which is comparable to that of noble Pt nanoparticles (18.60 mmol mg À1 h À1 ). It is proposed that the unusual catalytic rate arises from the special nanostructure of Co 0.85 Se and a positive synergetic effect between Co 0.85 Se and graphene. The results show that the ultrathin Co 0.85 Se which possesses a half-metallic character is a promising noble-metal-free cocatalyst for practical photocatalytic hydrogen production application.

3D Metallic Ti@Ni0.85Se with Triple Hierarchy as High‐Efficiency Electrocatalyst for Overall Water Splitting

“…Importantly, the Ni 2p 3/2 peak (855.8 eV) in Ni 0.85 Se positively shifted compared with metallic Ni (852.9 eV), and the Se 3d 3/2 (55.5 eV) and Se 3d 5/2 (54.5 eV) peaks negatively shifted compared with elemental Se (3d 3/2 55.7 eV and 3d 5/2 54.9 eV). Clearly, some electron density was transferred from Ni (δ + ) to Se (δ − ), which was also previously observed in Co 0.85 Se and Co 3 Se 4 . In addition to the charge transfer behavior, the intrinsic electronic structure of the electrocatalyst is considered to be important for the electrocatalytic performance.…”

“…This not only enhances the stability of the Ti@Ni 0.85 Se‐THA but also forms an integrated electrocatalytic system with efficient electron and mass transfer . (2) Owing to the charge‐transfer characteristics and metallic behavior of Ni 0.85 Se, the electron transportation in the Ti@Ni 0.85 Se‐THA electrode surface and the current collector (Ti mesh) could be significantly promoted . (3) The electrochemical surface area of the Ti@Ni 0.85 Se‐THA electrode was very high compared with Ti@Ni 0.85 Se‐NSA, which was responsible for the increased number of active sites .…”

Charge Transport in Two‐Photon Semiconducting Structures for Solar Fuels

“…A variety of noble‐metal‐free cocatalysts have been integrated with graphene–semiconductor composites, such as MoS 2 , Co 0.85 Se, NiO x , Ni(OH) 2 , and RuO 2 . In these materials, not only are the electron–hole pairs separated but there are more sites available for reduction.…”

Metal Phosphides as Co‐Catalysts for Photocatalytic and Photoelectrocatalytic Water Splitting

“…However, high prices have seriously limited their large‐scale application and searching for novel inexpensive materials and increasing their efficiency to rival the performance of Pt are significant demands. During the past few decades, a number of materials based on earth‐abundant elements, such as the first‐row transition metals (e.g., Fe, Co, Ni, Cu), have been recognized as good co‐catalysts for hydrogen evolution and some of them have been widely acknowledged. For example, since Li and co‐workers demonstrated that MoS 2 could act as a robust co‐catalyst for photocatalytic water reduction, various Mo‐based co‐catalysts (e.g., Mo 3 S 4 , MoS x , Cu 2 MoS 4 ) have also been extensively developed .…”