Development of photochemical and electrochemical cells for operando X-ray absorption spectroscopy during photocatalytic and electrocatalytic reactions.
Development of photochemical and electrochemical cells for operando X-ray absorption spectroscopy during photocatalytic and electrocatalytic reactions.
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开发光催化和电催化反应过程中原位 X 射线吸收光谱的光化学和电化学电池。
DOI：
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
J. Lercher
中科院分区：
文献类型：
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作者：
Rachit Khare;A. Jentys;J. Lercher
光化学和电化学反应是高度相关的过程，用于（i）转化化学品（例如异丙醇光还原为丙酮，苯甲醛电化学氢化为苯甲醇等），和（ii）可持续能源生产（例如CO2光还原为甲醇、电催化H2析出反应）。因此，重要的是要监测的结构变化，并了解光催化和电催化反应条件下的活性中心的属性。操作X射线吸收光谱（XAS）提供了在实际反应条件下研究活性中心性质的手段。在这方面的贡献，我们描述了光催化和电催化反应过程中的光化学和电化学电池的成功发展operando XAS测量。我们已经使用操作光化学电池来监测在可见光照射下经由光沉积在石墨氮化碳纳米片（g-C3 N4-ns）上形成Pt纳米颗粒，并且观察到高度分散的Pt纳米颗粒的形成，其估计尺寸为约2.5nm并且>60%分散。我们还测试了该电池，以跟踪在析氢反应（HER）期间Pt/TiO 2和Pt/g-C3 N4-ns中Pt的氧化态。我们观察到，Pt主要存在于金属（还原）Pt 0物种在HER条件下，PtOx物种被部分还原，从PtIV的Pt 0照射后，与UV或可见光。在光化学电池中获得的H2释放速率（Pt/TiO 2上为12.1 mmol g-1 h-1，Pt/g-C3 N4-ns上为1.01 mmol g-1 h-1）与在标准顶部照射的光反应器中获得的H2释放速率（Pt/TiO 2上为16.6 mmol g-1 h-1，Pt/g-C3 N4-ns上为1.76 mmol g-1 h-1）相当。采用操作电化学电池对苯甲醛电催化加氢过程中Pd/C电催化剂中Pd的结构和氧化态的变化进行了监测。结果表明，Pd/C中的Pd以部分还原状态存在（约80%Pd0和约20%PdII），并且Pd纳米颗粒在ECH反应条件下施加外电势时不会降解。
Photochemical and electrochemical reactions are highly relevant processes for (i) transforming chemicals (e.g. photoreduction of isopropanol to acetone, electrochemical hydrogenation of benzaldehyde to benzyl alcohol, etc.), and (ii) sustainable energy production (e.g. photoreduction of CO2 to methanol, electrocatalytic H2 evolution reaction). It is therefore of importance to monitor the structural changes and to understand the properties of active sites under photocatalytic and electrocatalytic reaction conditions. Operando X-ray absorption spectroscopy (XAS) provides the means to investigate the nature of active sites under realistic reaction conditions. In this contribution, we describe the successful development of photochemical and electrochemical cells for operando XAS measurements during photocatalytic and electrocatalytic reactions. We have used the operando photochemical cell to monitor the formation of Pt nanoparticles on graphitic carbon nitride nanosheets (g-C3N4-ns) via photodeposition under visible light illumination and observed the formation of highly dispersed Pt nanoparticles with an estimated size of ∼2.5 nm and >60% dispersion. We have also tested this cell to follow the oxidation state of Pt in Pt/TiO2 and Pt/g-C3N4-ns during H2 evolution reaction (HER). We observed that Pt predominantly existed as metallic (reduced) Pt0 species under HER conditions, and that PtOx species were partially reduced from PtIV to Pt0 upon illumination with UV or visible light. The rates of H2 evolution obtained in the photochemical cell (12.1 mmol g-1 h-1 on Pt/TiO2 and 1.01 mmol g-1 h-1 on Pt/g-C3N4-ns) were comparable to that obtained in a standard top-irradiated photoreactor (16.6 mmol g-1 h-1 on Pt/TiO2 and 1.76 mmol g-1 h-1 on Pt/g-C3N4-ns). The operando electrochemical cell was successfully tested to monitor the changes in the structure and oxidation state of Pd in Pd/C electrocatalyst during electrocatalytic hydrogenation (ECH) of benzaldehyde. It was demonstrated that Pd in Pd/C was present in a partially reduced state (∼80% Pd0 and ∼20% PdII) and Pd nanoparticles did not degrade upon the application of an external potential under ECH reaction conditions.
影响因子：
15
作者：
Gorlin, Yelena;Lassalle-Kaiser, Benedikt;Benck, Jesse D.;Gul, Sheraz;Webb, Samuel M.;Yachandra, Vittal K.;Yano, Junko;Jaramillo, Thomas F.
通讯作者：
Jaramillo, Thomas F.