Ni-Co bimetallic decorated dodecahedral ZIF as an efficient catalyst for photoelectrochemical degradation of sulfamethoxazole coupled with hydrogen production

In this work, a NiCo bimetallic ZIF (BMZIF) dodecahedron material has been synthesized by the precipitation approach and then used for simultaneously photoelectrocatalytic degradation of sulfamethoxazole (SMX) and hydrogen production. The combination of Ni/Co loading in ZIF structure increased the specific surface area 1484 (m2 g-1) and photocurrent density (0.4 mA cm-2), which can facilitate the good charge transfer efficiency. In presence of peroxymonosulfate (PMS, 0.1 mM), the complete degradation of SMX (10 mg L-1) was achieved at initial pH of 7 within 24 min, with the pseudo-first-order rate constants of 0.18 min-1 and TOC removal efficiency of 85 %. Radical scavenger experiments affirm that •OH radicals were the primary oxygen reactive species to drive the SMX degradation. Along with SMX degradation at the anode, the H2 production was observed at the cathode (140 μmol cm-2 h-1), which was 1.5 and 3 times higher than that of Co-ZIF and Ni-ZIF, respectively. The superior catalytic performance of BMZIF was assigned to the distinctive internal structure and synergistic effect between ZIF and Ni/Co bimetals, which improves light absorption and charge conduction efficiency. This study may provide insight into the new way to treat polluted water and simultaneously produce green energy using bimetallic ZIF in a PEC system.