Qianyu Chu,Guangmin Ren,Jingdan Zhao,Xiangchao Meng,Jie Meng,Zizhen Li
The photocatalytic nitrogen reduction reaction (NRR) is a sustainable green alternative to the Haber–Bosch process for ammonia production. However, due to the inert properties of dinitrogen, the photocatalytic activity in N2 reduction is still pretty low. Based on density functional theory calculations, this study finds that the formation energy of oxygen vacancies around the V site in InVO4 was significantly lower than that around the In site. This indicated that the V–O bond was thermodynamically less stable and tends to break preferentially. Therefore, selective cleavage of the V–O bond was achieved by subjecting InVO4 to transient high-temperature treatment via rapid Joule heating technology. This resulted in the directed construction of an InVO4-JH catalyst enriched with oxygen vacancies and exposing coordination-unsaturated V sites. The resulting InVO4-JH catalyst delivered a photocatalytic ammonia production rate of up to 35.28 μmol g−1 h−1 under ambient conditions without any sacrificial agent, while exhibiting excellent stability and reaction selectivity. Mechanistic studies and structural characterization confirmed that the formation of oxygen vacancies via V–O bond cleavage releases electrons, which reduce adjacent V5+ to V4+. This created localized electron-rich regions at exposed V sites. Theoretical calculations further confirmed that these exposed V sites act as the active centers of the reaction, not only significantly enhancing nitrogen adsorption but also substantially lowering the energy barrier of the hydrogenation step through alternative reaction pathways. This work provides a novel strategy for the rational design of highly efficient defect-engineered catalysts via targeted bond cleavage.
Mimicking natural photosynthesis to convert CO2 and H2O into highly valuable solar fuels is one of the ideal ways to alleviate the energy shortage and environmental pollution. However, the low mobility of photogenerated holes and sluggish H2O oxidation half reaction seriously retard the reduction efficiency of CO2 by photocatalysis. In this paper, we reported that the visible light-active SiC photocatalyst was inserted into the InVO4 nanoflower framework to form the dual Z-scheme heterojunction composited photocatalyst. The composited photocatalysts can not only neutralize the low mobility of photogenerated holes on SiC but also improve the H2O oxidation on InVO4 nanoflowers. This leads to an effective conversion of CO2 to CO without sacrificial agents under visible light irradiation as well as a good separation of photogenerated charge carriers in the composited photocatalyst for the subsequent reaction. In comparison to the parent InVO4 and SiC, the optimum CO yields over InVO4/SiC were 9.41 and 11.54 times, respectively. Under 3 h visible light irradiation, the yields of CO reach up to 142.6 μmol·g–1 and stability of O2 release over InVO4/SiC. This research offers a practical approach to developing an efficient photocatalyst for the conversion of CO2 with H2O.
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