Ni/Zn-ZIF-derived bamboo-like N-doped carbon nanotubes encapsulating Ni-based chalcogenides as efficient bifunctional electrocatalysts for hydrogen production and photovoltaics

Abstract

The construction of multiple active sites on the surface of carbon-based catalysts is extremely critical for enhancing their catalytic performance but still faces many challenges. In this study, we developed a catalyst by integrating Ni-based chalcogenides (NiSe or NiTe) with neighboring Ni–N_x dual active sites, using a Ni/Zn-zeolitic imidazolate framework as the precursor. During in situ selenization or tellurization, the precursor was transformed into bamboo-like N-doped carbon nanotubes, which provided a one-dimensional conductive pathway with reduced electron scattering and enhanced electron mobility, thereby facilitating efficient mass and charge transport. The encapsulated NiSe and NiTe nanoparticles not only protect the catalyst from electrochemical corrosion but also interact electronically with the surrounding Ni–N_x sites, contributing to both high activity and excellent stability in the hydrogen evolution reaction (HER) and triiodide reduction reaction (IRR). Consequently, NiSe@Ni–N–C and NiTe@Ni–N–C functioned as efficient HER electrocatalysts, requiring overpotentials of 121.8 mV and 109.3 mV, respectively, to reach a current density of 10 mA cm⁻² in alkaline electrolyte (1.0 M KOH). In photovoltaic device testing, NiTe@Ni–N–C offered the best power conversion efficiency of 8.30%, surpassing those of NiSe@Ni–N–C and Pt by 8.05% and 7.21%, respectively. First-principles density functional theory calculations were performed to elucidate the intrinsic catalytic mechanism, focusing on the electronic structure, chemical bonding, and ion-adsorption behavior of the electrocatalyst. This study presents a scalable strategy for constructing carbon-based catalysts with multiple active sites and integrated multifunctional components, offering new insights into the design of catalysts for energy-related applications.