The CeO₂/g-C₃N₄ hybrid is a kind of efficient photocatalyst with both photoinduced oxidation and reduction capability, which is of great concern in solar energy application. Herein, we reported a facile method for the synthesis of the CeO₂/g-C₃N₄ hybrid with enhanced CO₂ reduction and ciprofloxacin degradation performance using surface carboxylated g-C₃N₄ (C-g-C₃N₄) as the substrate. The characterization results demonstrated the abundant oxygen-containing groups of C-g-C₃N₄ in the CeO₂/C-g-C₃N₄ hybrid can effectively improve the dispersion of CeO₂ nanoparticles and enhance the interfacial bonding with the C-g-C₃N₄ substrate. Density functional theory (DFT) calculations showed that a built-in electric field was formed in the CeO₂/C-g-C₃N₄ heterojunction, which can greatly improve the charge separation and transfer efficiency. Consequently, the yield of CO and the ciprofloxacin degradation efficiency have been remarkably improved. The maximum CO yield through CO₂ photoreduction over 3%CeO₂/C-g-C₃N₄ was 9.083, 3.922, and 2.868 times higher than that of pure CeO₂, C-g-C₃N₄ and 3%CeO₂/g-C₃N₄ bulk, respectively. The 3%CeO₂/C-g-C₃N₄ heterojunction also showed excellent photoinduced oxidation activity for ciprofloxacin degradation with a 73% degradation efficiency in 2 h, which was 1.89 and 2.76 times higher than that of pure CeO₂ and C-g-C₃N₄, respectively. Furthermore, a good photostability for a five cycle test of CO₂ reduction was observed over the 3%CeO₂/C-g-C₃N₄ hybrid. The possible photocatalytic mechanism was investigated by theoretical calculations and capture experiments to further understand the charge transfer behavior over the CeO₂/C-g-C₃N₄ heterojunction for CO₂ reduction and pollutant degradation.

中文翻译：

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通过表面羧化作用增强CeO2 / g-C3N4杂化物的还原和氧化能力：性能和机理

CeO ₂ / gC ₃ N ₄杂化体是一种具有光诱导氧化和还原能力的高效光催化剂，在太阳能应用中备受关注。本文中，我们报道了一种以表面羧化的gC ₃ N ₄（CgC ₃ N ₄）为底物，具有增强的CO ₂还原和环丙沙星降解性能的CeO ₂ / gC ₃ N ₄杂化物的合成方法。表征结果表明，CeO _2中具有丰富的CgC ₃ N ₄含氧基团/ CgC ₃ N ₄杂化物可以有效地改善CeO ₂纳米颗粒的分散性，增强与CgC ₃ N ₄基体的界面键合。密度泛函理论（DFT）计算表明，在CeO ₂ / CgC ₃ N ₄异质结中形成了内置电场，可以大大提高电荷的分离和转移效率。因此，CO的产率和环丙沙星的降解效率得到了显着提高。通过3％CeO ₂ / CgC ₃ N _4上的CO _2光还原获得的最大CO产量分别是纯CeO ₂，CgC ₃ N ₄和3％CeO ₂ / gC ₃ N ₄本体的9.083、3.922和2.868倍。3％CeO ₂ / CgC ₃ N ₄异质结在环丙沙星降解中也表现出优异的光诱导氧化活性，在2小时内的降解效率为73％，分别比纯CeO ₂和CgC ₃ N ₄分别高1.89和2.76倍。。此外，在3％CeO ₂ / CgC上，观察到了CO ₅还原五周期测试的良好光稳定性。₃ N ₄混合动力。通过理论计算和捕获实验研究了可能的光催化机理，以进一步了解CeO ₂ / CgC ₃ N ₄异质结在CO ₂还原和污染物降解方面的电荷转移行为。