铋掺杂诱导表面重构与氧空位协同增强TiO₂光催化甘油制备合成气

Bismuth Doping-Induced Surface Reconstruction and Oxygen Vacancy Synergy for Enhanced Photocatalytic Glycerol Reforming to Syngas over TiO₂

摘要: 针对二氧化钛(TiO₂)光响应范围窄、光生载流子复合率高的问题，本研究采用Bi掺杂改性策略制备了高活性Bi-TiO₂光催化剂，系统考察了Bi掺杂对甘油光催化重整制备合成气性能的影响规律。结果表明，Bi以高价态离子(Bi^3+δ+)形式进入TiO₂晶格，通过与TiO₂的轨道杂化在带隙中形成新的中间态能级，使得催化剂的带隙从3.05 eV降低至2.62 eV，显著拓宽了催化剂的可见光吸收范围。同时，Bi^3+δ+及其诱导产生的氧空位缺陷可协同捕获光生电子，有效抑制了载流子复合，显著提升了催化剂的光催化性能。在模拟太阳光条件下，Bi-TiO₂催化剂表现出优异的甘油光催化重整性能。当Bi掺杂量为1.5 mmol·L⁻¹时，反应6 h后H₂产率达11.61 mmol·g⁻¹，CO产率达1.38 mmol·g⁻¹，分别为纯TiO₂的10.6倍和2.0倍。

Abstract: To address the issues of narrow light response range and high recombination rate of photogenerated carriers in titanium dioxide (TiO₂), this work employed a bismuth doping modification strategy to prepare high-performance Bi-TiO₂ photocatalysts. The influences of Bi doping on the performance of photocatalytic glycerol reforming to syngas were systematically investigated. Results indicate that Bi enters the TiO₂ lattice in the form of high-valence ions (Bi^3+δ+). Through the orbital hybridization with TiO₂, new intermediate energy levels are formed within the band gap, reducing the catalyst band gap from 3.05 eV to 2.62 eV and significantly broadening its visible-light absorption range. Simultaneously, Bi^3+δ+ and the induced oxygen vacancy defects can synergistically capture the photogenerated electrons, effectively suppressing carrier recombination and markedly enhancing the photocatalytic performance. Under simulated sunlight irradiation conditions, the Bi-TiO₂ catalysts exhibit excellent performance in photocatalytic glycerol reforming. At a Bi doping concentration of 1.5 mmol·L⁻¹, the H₂ yield reaches 11.61 mmol·g⁻¹ and the CO yield reaches 1.38 mmol·g⁻¹ after 6 h of reaction, which are 10.6-fold and 2.0-fold higher than those of pristine TiO₂, respectively.