NiO and Co1.29Ni1.71O4 derived from NiCo LDH form S-scheme heterojunction for efficient photocatalytic hydrogen evolution

Abstract

NiO and Co1.29Ni1.71O4 were generated in situ by oxidizing and calcining NiCo LDH (Layered Double Hydroxide) to erect an S-scheme heterojunction heterogeneous catalyst. After calcination, the lamellar structure of NiCo LDH becomes thinner and part of the lamellar porous, which can provide more active sites for hydrogen precipitation reaction. The amount of hydrogen released by the composite catalyst is 3 times that of NiCo LDH This in-situ generation method will allow NiO and Co1.29Ni1.71O4 to establish a close relationship, form a built-in electric field, and build an S-scheme heterojunction. NiO and Co1.29Ni1.71O4 have good band structure and band gap position matching. S-scheme heterojunction composite catalyst has the best light absorption intensity and photocurrent response, the smallest electronic impedance, and good electron and hole separation efficiency, thereby improving the performance of photocatalytic hydrogen evolution. It was confirmed by a large number of characterization studies.