Facile construction of self-assembled Cu@polyaniline nanocomposite as an efficient noble-metal free cocatalyst for boosting photocatalytic hydrogen production

Abstract

Photocatalytic Hydrogen production via water splitting is considered a sustainable ecofriendly pathway to replenish the current and future energy demands. In this study, the self-assembly synthesis of Cu nanospheres (∼8 nm) surrounded by a thin conductive layer of polyaniline (Cu@PANI) was rationally engineered via in˗situ polymerization. Afterward, it was successfully deposited onto the TiO2 surface to improve the photocatalytic activities for hydrogen production. The optimal Cu@PANI/TiO2 ternary photocatalyst produced a substantial hydrogen generation rate (HGR) of 17.7 mmol h−1 g−1, 207-fold higher than that of bare TiO2. The performance was considerably improved compared with (Cu–TiO2)/PANI and (PANI-TiO2)/Cu composites prepared by changing the deposition sequence of Cu and PANI. Such an improved activity was because of multiple transferring paths of photogenerated electrons in the composite. Interestingly, the as-prepared ternary photocatalyst exhibited superior hydrogen evolution compared with the binary hybrids (Cu/TiO2 and PANI/TiO2). The exceptional performance of Cu@PANI/TiO2 could be understood considering the distinctive electrical conductivity of PANI and heterojunction formed between PANI and TiO2, as well as the merits of the Schottky junction constructed between Cu and PANI. These superior features could efficiently suppress the recombination rate of the photogenerated electron–hole pairs and maximize the photocatalytic activity. This study provides new insights for understanding the effect of electron transfer pathways on photocatalytic activities.