Electrolyte Effect on Electrocatalytic Hydrogen Evolution Performance of One-Dimensional Cobalt-Dithiolene Metal-Organic Frameworks: A Theoretical Perspective

Abstract

In response to long-term energy-related crises driven by population growth, limited fossil fuel resources and climate change, scientists are looking for sustainable ways to produce renewable energy, including clean hydrogen fuels. Electrocatalytic water splitting is one of the most promising green technologies to produce H2.(1) However, the industrial electrocatalysts for hydrogen evolution reactions (HERs) often use expensive and scarce platinum group metal (PGM) based materials, e.g., Pt. As such, the electrocatalytic process for industrial H2 productions faces high materials cost. To this end, it is of vital importance to discover low-cost, high-performance materials to replace PGM based electrocatalysts.(2−4) Recently, the cobalt–dithiolene complex has been demonstrated to be an efficient electrocatalyst for HERs.(5−7) More interestingly, low-dimensional redox active cobalt–dithiolene metal–organic frameworks (MOFs) have been successfully synthesized with high electrocatalytic performance for HERs.(8,9) The redox active MOFs can offer specific advantages for electrocatalysis owing to their tunable pore metrics for ion transport, tunable electronic properties, high surface areas, high density of active catalytic sites, and quantum size effect.(10−14) Hence, the redox active cobalt–dithiolene MOFs are highly promising to replace the expensive PGM-based electrocatalysts. There have been some theoretical studies on the isolated cobalt–dithiolene monoanion.(15−18) Yet the theoretical studies on the electronic band structures of low-dimensional cobalt–dithiolene MOFs and external impacts on their catalytic HER performance, such as the electrolyte effect, are still rare, while of paramount importance.(19−21) Thus, limited guidance for the optimization of their operational conditions can be provided. To address this issue, it is imperative to conduct periodic first-principles calculations to understand the intrinsic properties of low-dimensional cobalt–dithiolene MOFs and the possible external impact on their catalytic HERs performance.