Charge Transfer-Induced Geometric Distortion in Ni(HCO3)2@CNT: Impact on Enhanced Catalytic Performance for Oxygen Evolution and Reduction Reactions

Abstract

Multidimensional carbon isotopes, such as carbon nanotubes (CNTs) and graphene, have been extensively researched as intrinsic catalytic materials or hetero supports for catalytically active metal sites, owing to their high conductivity, thermal stability, and chemical inertness. However, the enhanced catalytic performance of most transition metal-based catalysts on carbon supports is considered to be primarily due to improved carrier transport kinetics resulting from the conductivity of carbon supports, although there may be other possible effects that are not yet well understood. In this presentation, we propose CNT-decorated Ni(HCO3)2 (denoted as Ni(HCO3)2@CNT) as a bifunctional catalyst for both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). The sp3-like carbon in CNTs can induce charge transfer to the Ni active site within Ni(HCO3)2, which in turn induces strain in the Ni-O bond. This strain-induced Ni active site can stabilize the *O intermediate, leading to significantly lower potential barriers for the potential-determining steps of both OER and ORR compared to pristine Ni(HCO3)2. The adjustable catalytic activity enabled by interfacial charge transfer and its contribution to local structural distortion presents a straightforward approach to designing low-cost, highly efficient, and multifunctional catalysts for sustainable chemical energy conversion.