Tian Yan

Electrochemical CO2 reduction reaction (CO2RR) in acid can solve alkalinity issues while highly corrosive and reductive acidic electrolytes usually cause catalyst degradation. Inhibiting catalyst degradation is crucial for the stability of acidic CO2RR. Here, we reveal the microenvironment changes of dynamic Bi-based catalysts and develop a pulse chronoamperometry (CA) strategy to improve the stability of acidic CO2RR. In situ fluorescence mappings show that the local pH changes from neutral to acid, and the in situ Raman spectra reveal the dynamic evolution of interfacial water structures in the microenvironment. We propose that the surface charge properties of dynamic catalysts affect the competitive adsorption of K+ and protons, thereby causing the differences in local pH and CO2RR intermediate adsorption. We also develop a pulse CA strategy to reactivate catalysts, and the stability of acidic CO2RR is improved by 2 orders of magnitude for 100 h operation, which is higher than most reports on the stability of acidic CO2RR. This work gives insights on how microenvironment changes affecting the stability of acidic CO2RR, and provides guidance for designing stable catalysts in acidic electrolytes.

Due to the growing awareness of environmental protection and their economic benefits, there has been rapid development in the closed-loop supply chain (CLSC) in recent years, with a general occurrence of CLSCs led by collectors. Even with government support such as subsidies, the operation of CLSC still requires immense investment, such as purchasing recycling equipment. Nevertheless, the unprecedented economic recession during the post-pandemic era has heightened the risk of insufficient funding for CLSC. This highlights the importance of understanding the complexities involved in CLSC financing strategies, as they are crucial for ensuring the sustainability and resilience of CLSC in the face of challenges. To investigate the equilibrium decisions and financing strategy selection of CLSCs, we developed and analyzed a series of three-stage Stackelberg models, considering practical scenarios involving capital constraints, environmentally friendly green activities, government subsidies for End-of-Life (EOL) recycling, as well as introducing common trade credit financing and bank financing for generality. The findings demonstrate: (1) Under trade credit financing, it is always beneficial for the collector granting credit. Interest income can motivate the collector to recover more EOL products. (2) In addition to financing interest rates, government subsidies and remanufacturing cost savings can affect the financing strategy selection of the capital-constrained manufacturer. Our study provides guidance for managers in selecting optimal financing strategies under specific conditions. (3) The total profit of CLSC under trade credit financing is always higher and we propose a revenue-sharing contract to realize the win-win status with the optimal profit of CLSC. (4) Furthermore, our results underscore the importance of government recycling subsidies, remanufacturing cost savings, and the positive impact achieved by reducing recycling difficulties and enhancing customer awareness of green consumption.

As a potential alternative to the Haber–Bosch process for ammonia (NH3) synthesis, the electrocatalytic nitrate reduction reaction (NO3RR) has attracted extensive attention. The electrocatalytic conversion of NO3– to NH3 involves a complex 8e– reaction with various byproducts. By decomposing the overall reaction into a 2e– process from NO3– to NO2– and a 6e– process from NO2– to NH3, the two-step reaction can be strategically optimized to achieve efficient tandem catalysis. This work developed a NO2–-mediated pulsed electrocatalytic NO3RR by Co@Cu nanowire (NW) with dual active sites of the Co phase and Cu phase. The Cu phase rapidly accumulates NO2– at low potentials, while the Co phase efficiently converts NO2– to NH3 at high potentials, completing a time-separated tandem catalytic reaction. Ultimately, the Co@Cu NW achieved a maximum NH3 yield rate of 5148.6 μg·h–1·cm–2 and a maximum Faraday efficiency of 88.6% under pulsed potentials of −0.2 and −0.7 V versus the reversible hydrogen electrode in an electrolyte of 0.5 M SO42– and 0.1 M NO3–. Furthermore, in situ reflection absorption imaging and in situ total internal reflection imaging revealed that the pulsed strategy effectively enhances the utilization of NO2– and suppresses competitive hydrogen evolution reaction, thereby improving NO3RR performance.

With the proposal of the "carbon peak and carbon neutrality" goals, the utilization of renewable energy sources such as solar energy, wind energy, and tidal energy has garnered increasing attention. Consequently, the development of corresponding energy conversion technologies has become a focal point. In this context, the demand for electrochemical in situ characterization techniques in the field of energy conversion is gradually increasing. Understanding the microscopic electrochemical reactions and their mechanisms in depth is a common concern shared by both academia and industry. Therefore, the development of electrochemical in situ characterization techniques holds critical significance. This paper comprehensively reviews electrochemical in situ characterization techniques in the field of energy conversion from three aspects: spectral characterization techniques of electrochemical reactions, characterization techniques for the spatial distribution of electrochemical reactions, and optical characterization techniques for the surface refractive index associated with the spatial distribution of electrochemical reactions. These characteristics are described in detail, and the future development direction of in situ characterization technology is prospected, with the aim of promoting the advancement of electrochemical in situ characterization technology in the field of energy conversion, facilitating energy transformation, and thus advancing the goals of "carbon peak and carbon neutrality."