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Electrochemical conversion of CO2 to formic acid using Bismuth catalysts is one the most promising pathways for industrialization. However, it is still difficult to achieve high formic acid production at wide voltage intervals and industrial current densities because the Bi catalysts are often poisoned by oxygenated species. Herein, we report a Bi3S2 nanowire-ascorbic acid hybrid catalyst that simultaneously improves formic acid selectivity, activity, and stability at high applied voltages. Specifically, a more than 95% faraday efficiency was achieved for the formate formation over a wide potential range above 1.0 V and at ampere-level current densities. The observed excellent catalytic performance was attributable to a unique reconstruction mechanism to form more defective sites while the ascorbic acid layer further stabilized the defective sites by trapping the poisoning hydroxyl groups. When used in an all-solid-state reactor system, the newly developed catalyst achieved efficient production of pure formic acid over 120 hours at 50 mA cm–2 (200 mA cell current). Achieving high pure formic acid production from CO2 electroconversion is of high interest yet challenging. Here the authors report vitamin C functionalized Bi3S2 nanowire catalyst to achieve selective, active, and stable formic acid production. [ABSTRACT FROM AUTHOR]

Highlights: The electrochemical techniques utilizing metal-organic frameworks (MOFs)-based catalysts for converting CO2 into chemical species are discussed. The structure–activity relationship of MOF-based catalysts in electrocatalytic CO2 reduction reactions is thoroughly reviewed The challenges and opportunities of large-scale applications of MOF-based materials in electrochemical CO2 reduction reactions are discussed, and possible directions for the future development of MOFs and their derivatives are outlined. Electrochemically reducing CO2 to more reduced chemical species is a promising way that not only enables the conversion of intermittent energy resources to stable fuels, but also helps to build a closed-loop anthropogenic carbon cycle. Among various electrocatalysts for electrochemical CO2 reduction, multifunctional metal–organic frameworks (MOFs) have been employed as highly efficient and selective heterogeneous electrocatalysts due to their ultrahigh porosity and topologically diverse structures. Up to now, great progress has been achieved in the design and synthesis of highly active and selective MOF-related catalysts for electrochemical CO2 reduction reaction (CO2RR), and their corresponding reaction mechanisms have been thoroughly studied. In this review, we summarize the recent progress of applying MOFs and their derivatives in CO2RR, with a focus on the design strategies for electrocatalysts and electrolyzers. We first discussed the reaction mechanisms for different CO2RR products and introduced the commonly applied electrolyzer configurations in the current CO2RR system. Then, an overview of several categories of products (CO, HCOOH, CH4, CH3OH, and multi-carbon chemicals) generated from MOFs or their derivatives via CO2RR was discussed. Finally, we offer some insights and perspectives for the future development of MOFs and their derivatives in electrochemical CO2 reduction. We aim to provide new insights into this field and further guide future research for large-scale applications. [ABSTRACT FROM AUTHOR]

Industrially, artificial N2 fixation to NH3 mainly relies on the Haber–Bosch process which is operated in a harsh environment with large energy consumption and heavy serious greenhouse gas emission. Electrochemical N2 reduction offers a carbon-neutral and energy-saving method for NH3 synthesis under ambient conditions. Herein, we demonstrate the first use of ZrO2 nanoparticles as an earth-abundant electrocatalyst for NH3 synthesis from N2 and water under ambient conditions. In 0.1 M HCl, the electrocatalyst presents a large NH3 yield rate of 24.74 μg h−1 mgcat.−1 with a faradaic efficiency of 5.0% at −0.45 V vs. the reversible hydrogen electrode. It also demonstrates high electrochemical stability and excellent selectivity for NH3 generation. [ABSTRACT FROM AUTHOR]

The artificial N2 fixation to NH3 is dominated by the traditional Haber–Bosch process, which consumes large amounts of energy and natural gas with low energy efficiency and large amounts of CO2 emissions. Electrochemical N2 reduction is a promising and environmentally friendly route for artificial N2-to-NH3 fixation under milder conditions. Herein, we report that dendritic Cu acts as a highly active electrocatalyst to catalyze N2 to NH3 fixation under ambient conditions. When tested in 0.1 M HCl, such an electrocatalyst achieves a high faradaic efficiency of 15.12% and a large NH3 yield rate of 25.63 μg h−1 mgcat.−1 at −0.40 V versus a reversible hydrogen electrode. Notably, this catalyst shows high electrochemical stability and excellent selectivity toward NH3 synthesis. [ABSTRACT FROM AUTHOR]

Titanium‐based catalysts are needed to achieve electrocatalytic N2 reduction to NH3 with a large NH3 yield and a high Faradaic efficiency (FE). One of the cheapest and most abundant metals on earth, iron, is an effective dopant for greatly improving the nitrogen reduction reaction (NRR) performance of TiO2 nanoparticles in ambient N2‐to‐NH3 conversion. In 0.5 m LiClO4, Fe‐doped TiO2 catalyst attains a high FE of 25.6 % and a large NH3 yield of 25.47 μg h−1 mgcat−1 at −0.40 V versus a reversible hydrogen electrode. This performance compares favorably to those of all previously reported titanium‐ and iron‐based NRR electrocatalysts in aqueous media. The catalytic mechanism is further probed with theoretical calculations. [ABSTRACT FROM AUTHOR]

The synthesis of NH3 heavily relies on the Haber–Bosch process suffering from a large amount of CO2 emission and energy consumption. Possessing eco-friendly and sustainable characteristics, electrochemical reduction is considered as a promising candidate for artificial N2 fixation under ambient conditions, but efficient electrocatalysts are crucial for the N2 reduction reaction (NRR). In this communication, we report that perovskite La2Ti2O7 nanosheets behave as an efficient NRR electrocatalyst with excellent selectivity under ambient conditions. In 0.1 M HCl, this catalyst achieves a high NH3 yield rate of 25.15 μg h−1 mgcat.−1 with a faradaic efficiency of 4.55% at −0.55 V vs. a reversible hydrogen electrode. Notably, it also shows high electrochemical stability. [ABSTRACT FROM AUTHOR]