Semiconductors often have limited photocatalytic water-splitting performances owing to the narrow light absorption and low effective carrier density. In response to these challenges, we report the discovery of metallic amorphous cobalt boride (CoB) as the first first-row transition metallic photocatalyst. It was prepared via a simple chemical reduction method and performs efficient water splitting spanning the UV, visible light and near-infrared region (NIR) via interband transitions. It achieves bifunctional water splitting activities with H evolution rate of 202.3 μmol h g and O evolution rate of 74.8 μmol h g, superior to the existing (semi-)metallic photocatalysts. The material shows over 1 % apparent quantum efficiency (AQE) and 20 % incident photon to current conversion efficiencies (IPCE) at the NIR region >800 nm. Theoretical and photophysical experimental studies synergistically confirm that the metallic nature with high carrier concentrations and amorphous structure with abundant active sites contribute to the good water splitting performance of CoB. This research sets the foundation for the utilization of highly efficient transition metal-based metallic photocatalysts in photocatalysis across the entire solar spectrum.

中文翻译：

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非晶硼化钴作为第一个第一行过渡金属基金属光催化剂，可在 800 nm 范围内高效分解水

由于光吸收窄和有效载流子密度低，半导体的光催化水分解性能通常有限。为了应对这些挑战，我们报告了金属非晶硼化钴（CoB）的发现，作为第一个第一行过渡金属光催化剂。它是通过简单的化学还原方法制备的，并通过带间跃迁在紫外、可见光和近红外区域 (NIR) 进行有效的水分解。它实现了双功能水分解活性，析氢速率为202.3 μmol h g，析氧速率为74.8 μmol h g，优于现有的（半）金属光催化剂。该材料在 >800 nm 的 NIR 区域表现出超过 1% 的表观量子效率 (AQE) 和 20% 的入射光子电流转换效率 (IPCE)。理论和光物理实验研究协同证实，高载流子浓度的金属性质和具有丰富活性位点的非晶结构有助于CoB良好的水分解性能。这项研究为在整个太阳光谱范围内利用高效过渡金属基金属光催化剂进行光催化奠定了基础。