Gallium oxide semiconductors have been developed as effective photocatalysts for water splitting driven by UV light irradiation, but there is no relevant study for the CO₂ photoreduction application. Herein, we report the first investigation of β-Ga₂O₃ applying to photocatalytic CO₂ reduction under visible light irradiation by doping transition metal ions (M = V, Cr, Mn, Fe, Co, Ni and Cu) onto the framework. Using sol-gel method, a series of transition metal ions incorporated β-Ga₂O₃ have been successfully obtained, in which the transition metal substitution content is 2 mol%. The β-Ga₂O₃:M photocatalysts are characterized completely by diverse tests (e.g., XRD, XPS, UV–Vis DRS, SEM). The effective replacement of Ga³⁺ ion by M ions significantly expands the scope of spectral response from UV light to visible light, and Fe³⁺, Co²⁺, Ni²⁺ significantly enhance the photocatalytic activity under visible light irradiation. In these cases, CO and H₂ are evolved as the reduction products from CO₂ and H⁺ by the generated electrons, respectively. Among these effective catalysts we prepared, β-Ga₂O₃:Ni exhibits the most substantial CO formation rate of 14.3 μmol/h at 30 °C, and the selectivity for CO evolution exceeds 60.9%. Furthermore, the CO formation rate increases to 24.6 μmol/h after loading of Ag as the co-catalyst. The stability of the Ag/β-Ga₂O₃:Ni are verified after five cycle of CO₂ photoreduction under visible light.

镓氧化物半导体已经被开发为用于由紫外线照射驱动的水分解的有效光催化剂，但是对于CO _2光还原应用没有相关的研究。本文中，我们报道了通过将过渡金属离子（M  = V，Cr，Mn，Fe，Co，Ni和Cu掺杂到骨架上）将β- Ga ₂ O ₃应用于可见光辐照下光催化还原CO ₂的首次研究。使用溶胶-凝胶法成功地获得了一系列掺入β- Ga ₂ O ₃的过渡金属离子，其中过渡金属取代含量为2 mol％。该β-Ga ₂ O ₃：M光催化剂的特征完全通过各种测试（例如XRD，XPS，UV-Vis DRS，SEM）来表征。Ga ³⁺离子被M离子有效替代，极大地扩展了从紫外光到可见光的光谱响应范围，Fe ³⁺，Co 2 ⁺，Ni ²⁺显着增强了可见光照射下的光催化活性。在这些情况下，CO和H ₂分别通过所产生的电子从CO ₂和H ⁺还原为还原产物。在我们制备的这些有效催化剂中，β- Ga ₂O ₃：Ni在30°C下的最大CO生成速率为14.3μmol/ h，CO释放的选择性超过60.9％。此外，CO的形成率增加至24.6  μ摩尔/小时的Ag负载作为助催化剂之后。在可见光下经过5个循环的CO ₂光还原后，证实了Ag / β- Ga ₂ O ₃：Ni的稳定性。