Enhanced hydrogen evolution from CuO_x-C/TiO₂ with multiple electron transport pathways

by Xiuying Huang, Meng Zhang, Runze Sun, Gaoyuan Long, Yifan Liu, Weirong Zhao

Titanium dioxide nanoparticles co-modified with CuO_x (0≤x≤2) and carbonaceous materials were prepared with a simple hydrolysis and photo-reduction method for photocatalytic hydrogen generation. SEM/TEM and XPS analysis indicated that the carbonaceous materials were mostly coated on the TiO₂ surface and clearly revealed that the Cu species exhibited multivalence states, existing as CuO_x (0≤x≤2). The optimal catalyst showed a 56-fold enhanced hydrogen evolution rate compared with that of the pure C/TiO₂ catalyst. Further, an intensive multiple electron transfer effect originating from CuO_x and the carbonaceous materials is proposed to be responsible for the elevated photoactivity. CuO_x species serve as electron donors facilitating charge carrier transfer and proton reduction sites. The carbonaceous materials function as the “bridge” that transfers the electrons of TiO₂ to the CuO_x species, which provides a new route for electron transfer and reinforces the effect of CuO_x as a co-catalyst. In this study, the CuO_x and C co-modified TiO₂ catalyst was prepared with multiple electron transport pathways and enhanced hydrogen production evolution, which provides a deep understanding for the design of co-catalyst-based photocatalysts.