Regulating pore size of Co-P and Fe-Co-P mesoporous nanosheet array for coupling hydrogen evolution with Fenton reaction

Enhancing the energy efficiency of hydrogen evolution reaction (HER) represents a significant yet challenging goal. One promising approach to achieve this is developing catalysts with high activity and robust stability to couple HER with Fenton reaction. Herein, mesoporous nanosheet arrays (MNA) with featuring a mean pore size of 25 nm, was fabricated via a hydroxide precursor annealing strategy. The produced Co-P MNA 25 and Fe-Co-P MNA 25 are applied in HER and Fenton reaction, respectively. Compared to the MNA 12 synthesized by traditional method of self-growth and solid-phase phosphorization, the MNA 25 exhibited remarkable enhancement in performance, including a 49 % reduction in HER overpotential at 10 mA cm −2 , a 41 % increase in pseudo-first-order degradation kinetics of methylene blue in Fenton reaction, along with superior stability. In addition, the MNA 25 based flow reactor, which couples the two reaction and features a fastener-free design, demands just a minimal voltage of 1.61 V to drive, demonstrating impressive energy efficiency (81.56 % for HER and 2.77 g kWh −1 for Fenton) and application potential. More importantly, numerical simulations reveals that the larger pore size in MNA not only facilitated faster electrolyte diffusion, but also enhanced its impact buffer performance, thereby improving its catalytic activity and stability. Our work unveils the mechanism of mesopore size on the electrochemical performance of catalysts at the theoretical level, which offers a promising avenue for enhancing the energy efficiency of HER.