摘要
基于半导体光催化还原的人工光合成技术可在室温常压下将CO_(2)转化为碳基燃料,被认为是同时缓解能源短缺和环境危机的理想策略,但因已有光催化剂对太阳光利用不足、光生电荷复合快,致使CO_(2)光还原能量转换效率仍较低。采用水热法并结合表面浸渍过程首次制备出无定型CoOx/WO_(3-x)复合光催化剂,通过XRD、TEM、XPS、EPR和紫外-可见-近红外吸收光谱等测试技术对催化剂的晶相组成、微观形貌、光吸收特性与氧空位缺陷进行系统表征。CO_(2)光还原实验结果表明可见-近红外光照射3 h后,WO_(3-x)为催化剂仅可检测到3.2μmol·g^(−1)的CH4,复合CoO_(x)可显著提升WO_(3-x)的CO_(2)光催化还原性能,相同条件下最优催化剂2.5wt%CoO_(x)/WO_(3-x)的CO与CH4产生量分别可达78.2和19.7μmol·g^(−1)。引入氧空位可在WO_(3-x)的能带结构中形成一新的中间能级,增强近红外光吸收并使催化剂表面产生局部温升;复合CoO_(x)可在调控WO_(3-x)导带电势的同时,增强光生电荷的分离与迁移,光热效应和CoO_(x)助催化剂的协同作用是CO_(2)光催化转化性能增强的主要原因。此外,复合光催化剂CoO_(x)/WO_(3-x)具有优异的长期催化与结构稳定性。
The conversion of CO_(2)into carbon-based fuels through artificial photosynthesis technology based on semiconductor photocatalytic reduction has been identified as an ideal strategy to alleviate energy shortage and environmental crisis.However,due to insufficient utilization of solar energy and rapid recombination of photogenerated charges for the reported photocatalysts,the energy conversion efficiency of CO_(2)photoreduction is still low.Amorphous CoO_(x)/WO_(3-x)composite photocatalysts were synthesized by a hydrothermal method combining with surface impregnation process for the first time.Crystal phase composition,microstructure,optical absorption properties and oxygen vacancy defects of the prepared catalysts were systematically characterized by XRD,TEM,XPS,EPR and UV-Vis-NIR DRS.The results of CO_(2)photoreduction experiments show that only 3.2μmol·g^(−1) CH_(4) can be detected when using WO_(3-x)as a catalyst after Vis-NIR light irradiation for 3 h,whereas introducing CoO_(x) can significantly boost the CO_(2)photocatalytic reduction performance of WO_(3-x).Under the same experimental conditions,the yield of CO and CH_(4) on 2.5wt%CoO_(x)/WO_(3-x)catalyst can reach 78.2 and 19.7μmol·g^(−1) respectively.Introducing oxygen vacancies can form a new intermediate energy level in the band structure of WO_(3-x),which enhances NIR absorption and causes local temperature rise of the catalysts surface.Incorporating CoO_(x) contributes to enhance the separation and migration of photogenerated charges,and meanwhile can regulate the conduction-band potential of WO_(3-x).The synergistic effect of photothermal effect and CoO_(x) cocatalyst is the primary reason for the promoted performance of CO_(2)photocatalytic conversion.Additionally,the composite photocatalysts CoO_(x)/WO_(3-x)shows excellent long-term catalytic and structural stability.
作者
杨娟
田然
王大钊
戴俊
杜智华
YANG Juan;TIAN Ran;WANG Dazhao;DAI Jun;DU Zhihua(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization,Jiaozuo 454003,China;School of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454003,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2023年第9期5158-5169,共12页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(52074103
U2004194)
河南省科技攻关重点项目(222102320095)
河南省教育厅重点科研项目(21 A440008)。
