Elucidating the formation and active state of Cu co-catalysts for photocatalytic hydrogen evolution

Abstract

The design of active and selective co-catalysts constitutes one of the major challenges in developing heterogeneous photocatalysts for energy conversion applications. This work provides a comprehensive insight into thermally induced...

Cu5FeS4 quantum dots as a single-component photo-assisted electrocatalyst for efficient hydrogen evolution

“…1j shows two distinct characteristic peaks at 931.3 and 951.3 eV that can be indexed to Cu + . 31,32 Also, the binding energy of Cu 2p 3/2 at 951.3 eV is characteristic for cuprous compounds, which further proves the existence of Cu + in Cu 5 FeS 4 QDs. 33 The Fe 2p spectrum in Fig.…”

Efficient Photocatalytic H2 Evolution by Hexaniobate Nanosheets Grafted with Copper Nanoclusters

“…Indeed, recent studies with TiO 2 and Cu showed that heat treatments at around 100-150 °C can improve TiO 2 and Cu interaction without inducing Cu diffusion into the oxide, and consequently, it enhances the photocatalytic H 2 production. [30] In contrast, when no heat treatment was applied, the CuÀ TiO 2 linkage strength was found to be weak, since more than 60 % of the Cu content leached from TiO 2 after washing, or at high temperatures, ion diffusion into the semiconductor lattice hinders the proton reduction. In both cases, the H 2 evolution performance decreased significantly.…”

“…al, [24] Chen et. al, [29] and more recently by Schubert et al [30] . It is suggested that the reduction of Cu +2 centers could be occurring during the sample preparation as an effect of the scattered light or even in situ during XPS analysis.…”

“…Thus, our results showed that the interaction between Cu and the hexaniobate surface is highly beneficial for photocatalysis and in our case, it was achieved at mild temperatures (90 °C) and without any chemical reducing agent. Indeed, recent studies with TiO 2 and Cu showed that heat treatments at around 100–150 °C can improve TiO 2 and Cu interaction without inducing Cu diffusion into the oxide, and consequently, it enhances the photocatalytic H 2 production [30] . In contrast, when no heat treatment was applied, the Cu−TiO 2 linkage strength was found to be weak, since more than 60 % of the Cu content leached from TiO 2 after washing, or at high temperatures, ion diffusion into the semiconductor lattice hinders the proton reduction.…”

Insight into the surface property modification-enhanced C3N4 performance of photocatalytic nitrogen fixation

“…6 Heterogeneous catalysts are in different states from the reactants they catalyze in different phase reactions. When it comes to the improvement of the activity of the catalysts in heterogeneous reactions, besides the adjustment of the active sites 7–9 such as doping and adjusting the size of the active components, the surface properties 10–13 are important factors affecting the reaction rate of heterogeneous reactions. The photocatalytic nitrogen reduction reaction (NRR) for ammonia synthesis is a typical example.…”