In situX-ray diffraction and X-ray absorption spectroscopy of electrocatalysts for energy conversion reactions

Abstract

In the face of climate change and rising energy consumption, the electrochemical oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and electrochemical CO2 reduction reaction (CO2RR) are promising catalytic processes...

Operando Cooperated Catalytic Mechanism of Atomically Dispersed Cu−N4 and Zn−N4 for Promoting Oxygen Reduction Reaction

“…Subsequently, the distinct energy decrease by 1.1 eV can be observed for Cu K‐edge from 0.8 to 0.3 V, suggesting Cu gradually reduce as the ORR proceed. Finally, it nearly recovers to the initial state after reaction only accompanying by slightly positive shift [39–41] . The similar phenomenon has been observed for the electrocatalytic CO 2 reduction reactions [38, 42] …”

Operando Cooperated Catalytic Mechanism of Atomically Dispersed Cu−N4 and Zn−N4 for Promoting Oxygen Reduction Reaction

“…Finally,i tn early recovers to the initial state after reaction only accompanying by slightly positive shift. [39][40][41] Thesimilar phenomenon has been observed for the electrocatalytic CO 2 reduction reactions. [38,42] In order to clarify the change of Cu single atom during the invisible reaction process,t he EXAFS spectra were further analyzed as shown in Figure 4c.I mportantly,t he intensity of Cu À Nbond at 1.5 gradually decrease as the ORR proceed, accompanying by anew bond of CuÀCu at around 2.2 could be observed at the applied potential of 0.4-0.3 V. EXAFS fitting curves were also conducted to obtain the quantitative structural configuration of Cu (Figure 4d-f,T able S7).…”

Tuning Reconstruction Level of Precatalysts to Design Advanced Oxygen Evolution Electrocatalysts

“…The parameters of phase/electronic/geometrical structures, oxidation/spin states, and the morphology should be systemically considered [ 53 , 79 , 89 , 90 , 91 , 92 , 93 ]. Furthermore, in situ/operando spectroscopic techniques are crucial to identify the actual active species, providing greater insights into the relationship between the structure and activity of the studied catalysts [ 45 , 75 , 82 , 87 , 94 , 95 , 96 , 97 , 98 ].…”

“…Generally, it is difficult to capture intermediates with a short lifetime, or to observe dynamic changes by ex situ characterization approaches. To track the surface change during an electrochemical reaction, in situ/operando techniques, specifically in situ/operando XRD/XPS/TEM/XAS/Raman methods, are the most powerful tools [ 61 , 63 , 82 , 94 , 138 , 139 ]. For example, in situ XAS can provide informative data regarding dynamic changes of the valence state, coordination number, and bond length [ 72 , 81 , 94 , 140 ].…”

“…To track the surface change during an electrochemical reaction, in situ/operando techniques, specifically in situ/operando XRD/XPS/TEM/XAS/Raman methods, are the most powerful tools [ 61 , 63 , 82 , 94 , 138 , 139 ]. For example, in situ XAS can provide informative data regarding dynamic changes of the valence state, coordination number, and bond length [ 72 , 81 , 94 , 140 ]. Meanwhile, the in situ/operando Raman technique is sensitive to structural changes at different stages under a wide range of electrochemical reaction conditions [ 72 , 82 , 97 , 141 ].…”