The ultimate goal of photocatalytic CO₂ reduction is to achieve high selectivity for a single product with high efficiency. One of the most significant challenges is that expensive catalysts prepared through complex processes are usually used. Herein, gram-scale cubic silicon carbide (3C-SiC) nanoparticles are prepared through a top-down ball-milling approach from low-priced 3C-SiC powders. This facile mechanical milling strategy ensures large-scale production of 3C-SiC nanoparticles with an amorphous silicon oxide (SiO_x) shell and simultaneously induces abundant surface states. The surface states are demonstrated to trap the photogenerated carriers, thus remarkably enhancing the charge separation, while the thin SiO_x shell prevents 3C-SiC from corrosion under visible light. The unique electronic structure of 3C-SiC tackles the challenge associated with low selectivity of photocatalytic CO₂ reduction to C₁ compounds. In conjugation with efficient water oxidation, 3C-SiC nanoparticles can reduce CO₂ into CH₄ with selectivity over 90%.

中文翻译：

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球磨立方碳化硅纳米粒子在可见光照射下高选择性光催化将CO ₂还原为CH ₄。

光催化还原CO ₂的最终目的是为单一产品高效地实现高选择性。最重大的挑战之一是通常使用通过复杂工艺制备的昂贵催化剂。本文中，通过自上而下的球磨方法，从低价的3C-SiC粉末中制备出了克级立方碳化硅（3C-SiC）纳米颗粒。这种简便的机械铣削策略可确保大规模生产带有无定形氧化硅（SiO _x）壳的3C-SiC纳米颗粒，并同时引发丰富的表面状态。已证明表面状态会俘获光生载流子，从而显着增强电荷分离，而薄SiO _x外壳可防止3C-SiC在可见光下腐蚀。3C-SiC的独特电​​子结构解决了光催化还原CO ₂对C ₁化合物的选择性低的挑战。与有效的水氧化结合，3C-SiC纳米颗粒可以将CO ₂还原为CH ₄，选择性超过90％。