Regulation of eg orbital occupancy in Ni-based metal-organic frameworks for efficient hydrogen peroxide electrosynthesis

• Published in: Applied catalysis. B, Environmental Environmental, 2024-12, Vol.358, p.124436, Article 124436
• Main Authors: Tang, Hong-Tao, Tang, Zi-Jun, Li, Ruo-Lin, Tian, Lei, Wang, Renjie, Pu, Shouzhi, Liu, Zhao-Qing
• Format: Article
• Language: English
• Subjects: eg orbital occupancy; Hydrogen peroxide electrosynthesis; Metal-organic frameworks; Oxo-intermediates; Oxygen reduction reaction
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2024.124436

Subject to the binding strength between the cathode and the oxo-intermediates, the hydrogen peroxide (H2O2) electrosynthesis with high productivity and high selectivity in oxygen reduction reaction (ORR) cannot be achieved simultaneously. In this work, the dual-metal-organic frameworks (NiFe-MOFs) is designed and synthesized, in which the eg orbital occupancy of Ni nodes is regulated by the super-exchange effect of Ni(2+σ)+-O-Fe(3-σ)+ bond. As a result, the binding strength between the cathode and the oxo-intermediates (*O2, *OOH) is optimized, which efficiently promotes oxygen reduction kinetics and inhibits O-O bond breakage. The H2O2 yield of NiFe-MOFs cathode reaches 1.83 mol·g−1·h−1 with a Faraday efficiency of 96.3 % at 0.5 V vs. RHE, which is far superior to Ni-MOFs (0.21 mol·g−1·h−1, 65.4 %), Fe-MOFs (0.65 mol·g−1·h−1, 57.5 %). This work offers a new strategy to design and develop cathodic catalysts for H2O2 electrosynthesis with high productivity and high selectivity. [Display omitted] •H2O2 synthesis with high yield and selectivity is achieved on NiFe-MOFs cathode.•The super-exchange effect of Ni-O-Fe regulates the eg orbital occupancy of Ni node.•The binding strength with oxo-intermediates is optimized to enhance 2e- ORR.