Solar light-responsive Ag/CdS/TNTs (TiO2 nanotubes) photocatalysts for enhanced CO2 photoreduction and hydrogen evolution

Solar-to-chemical energy conversion via heterogeneous photocatalysis is one of the effective approaches to tackle the growing environmental and energy challenges. Homogeneously dispersed silver nanoparticles (Ag NPs) and cadmium sulfide nanoparticles (CdS NPs) with average particle size not>20 nm were fabricated on the surface of titanium dioxide nanotubes (TNTs) (Ag/CdS/TNTs) with the help of sodium dodecyl benzene sulfonate (SDBS). Herein, more surface active sites are created on the surface of nanocomposites. The experimental results demonstrate that the photocurrent intensity of the nanocomposites obviously increased, which effectively im-proves the photocatalytic activity. The results of photocatalytic experiments indicated that using triethanolamine (TEOA) and acetonitrile (MeCN) as sacrificial agents, the nanocomposites afford the CO yield from CO2 (1455.6 mu mol center dot g- 1 center dot h-1). Besides, Ag/CdS/TNTs nanocomposites displayed the H2 evolution rate of 3700.57 mu mol center dot g- 1 center dot h-1, which was twice as much as pure TiO2 NPs. The increase in the photocatalytic ability of the nanocomposites is basically attributed to the three materials formation S-scheme heterojunction which reduce the recombination probability of the photo-induced electrons and holes and thus enhances the photocatalytic activitys. Ultimately, a photocatalytic reaction mechanism is proposed for Ag/CdS/TNTs nanocomposites in the reduction of CO2.