Cu₂ZnSnS₄–PtM (M = Co, Ni) Nanoheterostructures for Photocatalytic Hydrogen Evolution

Abstract

ABSTRACT:We report the synthesis and photocatalytic and magnetic characterization of colloidal nanoheterostructures formed by combining a Pt-based magnetic metal alloy (PtCo, PtNi) with Cu 2 ZnSnS 4 (CZTS). While CZTS is one of the main candidate materials for solar energy conversion, the introduction of a Pt-based alloy on its surface strongly influences its chemical and electronic properties, ultimately determining its functionality. In this regard, up to a 15-fold increase of the photocatalytic hydrogen evolution activity was obtained with CZTS−PtCo when compared with CZTS. Furthermore, two times higher hydrogen evolution rates were obtained for CZTS−PtCo when compared with CZTS−Pt, in spite of the lower precious metal loading of the former. Besides, the magnetic properties of the PtCo nanoparticles attached to the CZTS nanocrystals were retained in the heterostructures, which could facilitate catalyst purification and recovery for its posterior recycling and/or reutilization.

Enhanced Photocatalytic Hydrogen Evolution of NiCoP/g‐C3N4 with Improved Separation Efficiency and Charge Transfer Efficiency

“…Numerous efforts have been devoted to improving the separation efficiency of g-C 3 N 4 . [16][17][18][19] It is well known that noblem etalss uch as platinum [11] and platinum-based species [20,21] have been regarded as effective cocatalysts for efficient photocatalytic hydrogen production. However, its large-scale commercialization is limited due to its high cost and scarcity.T herefore, it is of great importance to develop highly efficient and low-cost cocatalysts for photocatalytic hydrogen production.…”

Multifunctional Copper‐Based Quaternary Chalcogenide Semiconductors Toward State‐of‐the‐Art Energy Applications

“…Pt has more pronounced effect on hydrogen evolution efficiencies than Au as compared to bare CZTS. The efficiencies could be further improved by incorporation of PtCo alloy in different composition (Co/Pt ratios: Co/Pt=0.5; Co/Pt=1; Co/Pt=2) as compared to only Pt as shown in Figure f, g, h, i . Comparison of the various Co/Pt ratio shows that the ratio of Co/Pt=1 gives maximum enhancement in the hydrogen evolution efficiencies as compared to bare CZTS which is shown in Figure j.…”

“…The effect of incorporating plasmonic and noble Au and noble Pt has been explored as well by Dilsaver et al ., Yu et al . and few other groups . In case of plasmonic as well as noble metal Au, the surface plasmon effect (SPR) helps in the absorption of more radiation through near field effect.…”

Enhanced Separation Efficiency of PtNix/g‐C3N4 for Photocatalytic Hydrogen Production

“…As depicted in Figure , the radius diameter on the EIS Nyquist plot of 2.5 % PtNi x /g‐C 3 N 4 is much smaller than that of pure g‐C 3 N 4 , which suggests that 2.5 % PtNi x /g‐C 3 N 4 features a more effective separation of electron–hole pairs and a faster charge‐transfer rate on the PtNi x /g‐C 3 N 4 interface . Consequently, the 2.5 % PtNi x /g‐C 3 N 4 has a better conductivity, which can be a reason for the high hydrogen production rate …”

“…Noble metals, such as platinum, have been regarded as effective co‐catalysts applied in photocatalytic H 2 evolution, but their use remained limited for practical application owing to their high‐cost and easy deactivation from the surface adsorption of poisonous intermediates or reaction products. Noble‐metal‐based bimetallic catalysts, to the best of our knowledge, have emerged as promising catalysts for oxygen reduction reaction, biomass energy conversion, as well as hydrogen evolution, which made it possible to reduce the amount of expensive noble metal used and further allow us to adjust the electronic and chemical properties of the noble metals, providing the catalysts with improved activity, selectivity, and stability. Platinum‐based co‐catalysts have been used to modify g‐C 3 N 4 , CdS, SiO 2 , and carbon nanofiber for the hydrogen production half‐reaction, showing significant enhanced hydrogen evolution than the original catalyst; however, little is known about the mechanism that these system undergo during the photocatalytic reaction and lead to efficient catalytic activity.…”