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Reusing spent anodes is a pivotal step for recycling lithium-ion batteries (LIBs). However, it proves challenging to completely eliminate Cu impurities from spent graphite (SG), which hinders the effective recycling of spent anodes. In this paper, a straightforward air oxidation method is proposed to directly upgrade spent anodes into stable CuO/C anodes by harnessing the inherent Cu impurities in spent anodes. The air oxidation process not only repairs the SG to some extent but also generates uniformly dispersed CuO nanoparticles, which chemically bind with the repaired graphite (RG) through Cu–O–C bonds. The specific discharge capacity of the CuO/RG anode can reach as high as 647 mA h g−1 even after 500 cycles (at 372 mA g−1 ). In addition, this program is found to reduce energy consumption and greenhouse gas emissions by ∼80% compared to previously reported CuO/C production programs. Clearly, this approach provides a new direction for large-scale recycling of spent LIBs and low-cost production of high-performance CuO/C anodes. [ABSTRACT FROM AUTHOR]

The non-graphitizable behavior of lignin has been well recognized as one of the most common issues hindering its valorization. In this study, we demonstrated the great potential of lignin for graphitization using a simple yet effective method of pretreatment using hot pressing. Lignin was found to form a more graphitizable structure with variable carbon–oxygen bonds and fewer carbonyl or ester structures upon hot pressing. The hot-pressed samples (lignin-15t) showed a dramatic increase in sp2 carbon and graphitic microcrystalline with increasing carbonization temperatures compared to the non-hot-pressed samples (lignin-0t). At only 1000 °C, the carbonized lignin-15t exhibited a clearly oriented graphitic structure with the d002 spacing of 0.3454 nm, which was significantly superior to the carbonized lignin-0t or any other lignin-derived carbon carbonized even under harsher conditions. At 1600 °C, the carbonized lignin-15t achieved a graphitization degree of 47.67% with abundant graphitic regions observed in its TEM images. This work can intrigue great interest in lignin graphitization and the applications of lignin-derived carbon materials. [ABSTRACT FROM AUTHOR]

Investigation of catalytic hydrogenation of CO2 to CO via the reverse water-gas shift (RWGS) was undertaken using Ni/SiO2-based catalysts. Among the array of catalysts tested, the Ni/SiO2 catalyst derived from the reduction of silicalite-1-encapsulated, ligand-protected Ni2+ (Ni0.2@S-1-red) exhibited promising performance. This catalyst demonstrated a CO2 conversion rate approaching the equilibrium conversion of RWGS, a selectivity for CO exceeding 99%, and a high space time yield of CO (9.7 mol gNi -1 h-1). The outcomes observed can be attributed to several factors, such as the highly dispersed Ni0 and Niδ+ species, as well as the presence of bridging oxygen of the Ni-O-Si structure, on which CO2 can be adsorbed moderately. The moderately bonded CO2 on Ni0.2@S-1-red allows for the efficient desorption of its reduced intermediate, i.e. *CO, resulting in the generation of gaseous CO at a rapid rate, consequently preventing its deep hydrogenation to CH4. Complementary Density Functional Theory (DFT) calculations were performed and revealed that CO molecules have poor adsorption and higher adsorption energy on the Ni@S-1 surface compared to the S-1 surface. This supports the rapid desorption of *CO and the observed high selectivity of CO. Moreover, the structure-activity correlation analysis further supports the claim of Ni0.2@S-1-red as a promising RWGS catalyst. [ABSTRACT FROM AUTHOR]