To identify the specific activity sites for both the HER and OER in experimental realized single transition-metal atom decorated graphene sheets, we assume the number of metal–C bonds (coordination) determines the adsorption strength of reaction intermediates on the metal atom sites. We find the strength weakens with the metal coordination number. Low-coordinated Ni sites, i.e. single-coordinated Ni on the zigzag edge, exhibit the highest activity toward HER, while high-coordinated Ni atoms, i.e. quadruple-coordinated Ni, demonstrate the best OER performance. This assumption has been further confirmed by a wide range of transition metals, including Mn, Fe, Co, Cu, and Pd. Our findings highlight a new family of efficient bifunctional catalysts for water splitting and offer a new paradigm for the design of single-atom HER/OER catalysts toward hydrogen production.

中文翻译：

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通过初步研究 了解单原子催化剂产生氢和氧的活性和选择性†

为了确定在实验实现的单过渡金属原子修饰的石墨烯片中HER和OER的特定活性位点，我们假设金属-C键（配位）的数量决定了反应中间体在金属原子位点上的吸附强度。我们发现强度随金属配位数而变弱。低镍协调网站，即单协调镍的锯齿边缘，表现出对她最高的活性，而高配位的Ni原子，即四重镍，表现出最佳的OER性能。广泛的过渡金属（包括Mn，Fe，Co，Cu和Pd）进一步证实了这一假设。我们的发现突出了用于水分解的高效双功能催化剂的新家族，并为设计单原子的HER / OER催化剂设计了新的制氢方法。