Electrochemical carbon dioxide reduction reaction (CO₂RR) can produce value-added hydrocarbons from renewable electricity, providing a sustainable and promising approach to meet dual-carbon targets and alleviate the energy crisis. However, it is still challenging to improve the selectivity and stability of the products, especially the C₂₊ products. Here we propose to modulate the electronic structure of copper oxide (CuO) through lattice strain construction by zinc (Zn) doping to improve the selectivity of the catalyst to ethylene. Combined performance and in situ characterization analyses show that the compressive strain generated within the CuO lattice and the electronic structure modulation by Zn doping enhances the adsorption of the key intermediate ^⋆CO, thereby increasing the intrinsic activity of CO₂RR and inhibiting the hydrogen precipitation reaction. Among the best catalysts had significantly improved ethylene selectivity of 60.5% and partial current density of 500 mA·cm⁻², and the highest C₂₊ Faraday efficiency of 71.47%. This paper provides a simple idea to study the modulation of CO₂RR properties by heteroatom doped and lattice strain.

The electrochemical nitrate reduction reaction (NO₃RR) to ammonia under ambient conditions is a promising approach for addressing elevated nitrate levels in water bodies, but the progress of this reaction is impeded by the complex series of chemical reactions involving electron and proton transfer and competing hydrogen evolution reaction. Therefore, it becomes imperative to develop an electro-catalyst that exhibits exceptional efficiency and remarkable selectivity for ammonia synthesis while maintaining long-term stability. Herein the magnetic biochar (Fe-C) has been synthesized by a two-step mechanochemical route after a pyrolysis treatment (450, 700, and 1000 °C), which not only significantly decreases the particle size, but also exposes more oxygen-rich functional groups on the surface, promoting the adsorption of nitrate and water and accelerating electron transfer to convert it into ammonia. Results showed that the catalyst (Fe-C-700) has an impressive NH₃ production rate of 3.5 mol·h⁻¹·g_cat⁻¹, high Faradaic efficiency of 88%, and current density of 0.37 A·cm⁻² at 0.8 V vs. reversible hydrogen electrode (RHE). In-situ Fourier transform infrared spectroscopy (FTIR) is used to investigate the reaction intermediate and to monitor the reaction. The oxygen functionalities on the catalyst surface activate nitrate ions to form various intermediates (NO₂, NO, NH₂OH, and NH₂) and reduce the rate determining step energy barrier (*NO₃ → *NO₂). This study presents a novel approach for the use of magnetic biochar as an electro-catalyst in NO₃RR and opens the road for solving environmental and energy challenges.

Electrocatalytic nitrate reduction reaction (NitRR) is an efficient route for simultaneous wastewater treatment and ammonia production, but the conversion of NO₃^- to NH₃ involves multiple electron and proton transfer processes and diverse by-products. Therefore, developing ammonia catalysts with superior catalytic activity and selectivity is an urgent task. The distinctive electronic structure of Cu enhances the adsorption of nitrogen-containing intermediates, but the insufficient activation capability of Cu for interfacial water restricts the generation of reactive hydrogen and inhibits the hydrogenation process. In this work, a Ce-doped CuO catalyst (Ce₁₀/CuO) was synthesized by in situ oxidative etching and annealing. The redox of Ce³⁺/Ce⁴⁺ enables the optimization of the electronic structure of the catalyst, and the presence of Ce³⁺ as a defect indicator introduces more oxygen vacancies. The results demonstrate that Ce₁₀/CuO provides an impressive ammonia yield of 3.88 (± 0.14) mmol cm^-2 h^-1 at 0.4 V vs. RHE with an increase of 1.04 mmol cm^-2 h^-1 compared to that of pure CuO, and the FE reaches 93.2% (± 3.4). In situ characterization confirms the doping of Ce facilitates the activation and dissociation of interfacial water, which promotes the production of active hydrogen and thus enhances the ammonia production efficiency.

Introduction: Iron is one of the most important needed elements for the growth and reproduction of living organisms. The detection of iron levels is important and developing fluorescent probes with excellent sensitivity for Fe³⁺ ions is of great significance. Carbon dot (CDs) is a new type of fluorescent nanomaterial based on abundant and low-cost carbon elements. The use of widely distributed renewable agricultural waste straw as a carbon precursor to prepare CDs sensor can not only reduce the pollution caused by burning straw to the atmospheric environment, but also achieve the transformation of resources from waste to treasure.Methods: In this study, CDs were obtained from corn stalk powder by pyrolysis and microwave process. The sensitivity and linear response range of CDs sensor was studied through analyzing the effect of different Fe³⁺ ions concentrations on the fluorescence quenching. The application of CDs in biological cell imaging was investigated using HGC-27 cells.Results: The fluorescence quenching showed a good linear relationship with the Fe3+ concentration in the range from 0 to 128 μM, and a low detection limit of 63 nM. In addition, the CDs have high recognition for Fe3+ ions. Meanwhile, the CDs have a low cytotoxicity and desirable biocompatibility, allowing the multicolor living cell imaging.Conclusion: The prepared CDs can be used as fluorescent sensors for the selective detection of Fe³⁺ ions and biological cell imaging. Our results supported that the conversion of agricultural waste into carbon nanomaterials has great potential to be developed.

The luminescence properties and excellent carrier transfer ability of carbon quantum dots (CQDs) have attracted much attention in the field of photocatalysis. In this work, we loaded the CQDs on the surface of Cu₂O to enhance the visible-light property of Cu₂O. Furthermore, the composite was used for selective oxidation of benzyl alcohol to benzaldehyde. The composite catalyst achieved high selectivity (90%) for benzaldehyde at room temperature, leveraging its visible-light-induced electron transfer properties and its photocatalytic activity for hydrogen peroxide decomposition. ·OH was shown to be the main reactive oxygen species in the selective oxidation reaction of benzyl alcohol. The formation of heterostructures of CQDs/Cu₂O promoted charge carrier separation and provided a fast channel for photoinduced electron transfer. This novel material exhibited enhanced levels of activity and stability for selective oxidation of benzyl alcohol. Potential applications of carbon quantum dot composites in conventional alcohol oxidation reactions are shown.