Abstract

Electrochemical CO₂ reduction reaction (CO₂RR) driven by sustainable energy has emerged as an attractive route to achieve the target of carbon neutral. Formate is one of the most economically viable products, and electrocatalytic CO₂RR to formate is a promising technology. High-pressure H-cell electrolyzer is easy to operate and allows high CO₂ solubility for realizing high current density, but the design of highly efficient catalysts for working under high CO₂ pressures remains challenging. Bismuth-based catalysts exhibit high formate selectivity, but suffer from limited activity. Here, we report a high-performance catalyst, which is derived from BiPO₄ nanopolyhedrons during electrocatalytic CO₂RR to formate in neutral solution under high CO₂ pressures. A high partial current density of formate (534 mA cm⁻²) and formate formation rate (9.9 mmol h⁻¹ cm⁻²) with a formate Faradaic efficiency of 90% have been achieved over BiPO₄-derived catalyst at an applied potential of −0.81 V vs. RHE under 3.0 MPa CO₂ pressure. We discover that BiPO₄ nanopolyhedrons evolve into metallic Bi nanosheets with rich grain boundaries in electrocatalytic CO₂RR under high CO₂ pressures, and the grain boundaries of the BiPO₄-derived catalyst play a vital role in promoting electrocatalytic CO₂RR to formate. Our theoretical studies reveal that the charge redistribution occurs at the grain boundaries of Bi surface, and this promotes CO₂ activation and increases HCOO* intermediate stability, thus making the pathway for CO₂RR to formate more selective and energy-favorable. This work not only demonstrates a highly efficient catalyst for CO₂RR to formate but also discovers a unique feature of catalyst evolution under high CO₂ pressures.

中文翻译：

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具有丰富晶界的铋纳米片可在高压下有效地将 CO2 电还原为甲酸盐

摘要

由可持续能源驱动的电化学CO ₂还原反应（CO ₂ RR）已成为实现碳中和目标的有吸引力的途径。甲酸盐是最经济可行的产品之一，电催化CO ₂ RR 制甲酸盐是一种很有前景的技术。高压H电池电解槽操作简单，CO _{2溶解度高，可实现高电流密度，但设计在高CO 2}压力下工作的高效催化剂仍然具有挑战性。铋基催化剂表现出高甲酸盐选择性，但活性有限。_{在这里，我们报告了一种源自 BiPO 4}的高性能催化剂_{在高CO 2}压力下电催化CO ₂ RR 在中性溶液中形成纳米多面体。在BiPO 4^衍生的催化剂上_，在应用电位^为−0.81 V与. RHE 在 3.0 MPa CO ₂压力下。我们发现BiPO _{4纳米多面体在高CO 2}压力下在电催化CO ₂ RR中演变成具有丰富晶界的金属Bi 纳米片，并且BiPO 的晶界_{4-衍生催化剂在促进电催化CO 2} RR 生成甲酸方面起着至关重要的作用。我们的理论研究表明，电荷重新分布发生在Bi表面的晶界处，这促进了CO ₂的活化并提高了HCOO*中间体的稳定性，从而使CO ₂ RR的生成途径更具选择性和能量优势。这项工作不仅展示了一种高效的 CO ₂ RR 甲酸催化剂，而且还发现了在高 CO ₂压力下催化剂演化的独特特征。