Design strategy of a Cu-based catalyst for optimizing the performance in the electrochemical CO2 reduction reaction to multicarbon alcohols.

The electrochemical CO2 reduction reaction (ECRR) is a promising method to reduce excessive CO2 emissions and achieve a sustainable carbon cycle. Due to the high reaction kinetics and efficiency, copper-based catalysts have shown great application potential for preparing multicarbon (C2+) products. C2+ alcohols have high economic value and use-value, playing an essential role in modern industry. Therefore, we summarize the latest research progress of the ECRR to synthesize C2+ alcohols on Cu-based catalysts and discuss the state-of-the-art catalyst design strategies to improve CO2 reduction performance. Moreover, we analyzed in detail the specific reaction pathways for the conversion of CO2 to C2+ alcohols based on DFT calculations. Finally, we propose the problems and possible solutions for synthesizing C2+ alcohols with copper-based catalysts. We hope that this review can provide ideas for devising ECRR catalysts for C2+ alcohols.

A clean and efficient process for simultaneous extraction of Li, Co, Ni and Mn from spent Lithium-ion batteries by low-temperature NH4Cl roasting and water leaching.

The recycling of valuable metals from spent lithium-ion batteries (LIBs) has great significance for environmental protection and resource conservation. In this paper, a low-temperature clean chlorination roasting-water leaching process was proposed to simultaneously extract Li, Ni, Co and Mn from cathode material (NCM) of spent LIBs. The temperature range of chlorination roasting was determined by thermodynamic analysis to be 250-600 °C. The effect of some factors on the conversion of valuable metals in the process of chlorination roasting and water leaching was systematically studied. The results showed that more than 98 % of Li, Co, Ni and Mn could be extracted under optimized chlorination roasting and water leaching conditions. The chlorination roasting mechanism and phase transformation evolution was determined by means of thermodynamic analysis, TG-DTA, XRD, SEM and EDS. The extraction of valuable metals was realized by the reaction of the metal oxides produced by the decomposition of NCM with NH4Cl or its evolved HCl to form water-soluble metal chlorides or chlorinated metal-ammonium complexes. The chlorination technique using NH4Cl provided an effective and clean approach for the simultaneous extraction of Li, Co, Ni and Mn from spent LIBs.

Optimization of Synergistic Leaching of Valuable Metals from Spent Lithium-Ion Batteries by the Sulfuric Acid-Malonic Acid System Using Response Surface Methodology.

A new environmentally friendly and economical recycling process for extracting metals from spent lithium-ion batteries (LIBs) using sulfuric acid and malonic acid as leaching agents is proposed. By applying Box-Behnken design (BBD) and response surface methodology (RSM) optimization techniques, the global optimal solution of the maximum leaching rate of metals in spent LIBs is realized. The results show that under the optimal conditions of 0.93 M H2SO4, 0.85 M malonic acid, and a liquid/solid ratio of 61 g·L-1, a temperature of 70 °C and 5 vol % of 30% H2O2, 99.79% Li, 99.46% Ni, 97.24% Co, and 96.88% Mn are recovered within 81 min. The error between the theoretical value and the actual value of the metal leaching rate predicted by the regression model is less than 1.0%. Additionally, the study of leaching kinetics reveals that the leaching process of Li, Ni, Co, and Mn in spent cathode materials was affected by the synergistic effect of interfacial mass transfer and solid product layer diffusion. Economic analysis reveals that evaluation index should be fully considered when formulating recovery processes for different metals. This process can reduce the environmental risks of heavy metal disposal and allow the reuse of metals recovered from spent LIBs.