H2 production via water electrolysis is of great significance in clean energy production, which, however, suffers from the sluggish kinetics of the anodic oxygen evolution reaction (OER). Moreover, the anode product, O2, which is of rather low value, may lead to dangerous explosions and the generation of membrane‐degrading reactive oxygen species. Herein, to address these issues of electrocatalytic H2 production, we summarize the most recent advances in three stages based on the benefit increments and various electron donation routes, which are: 1) electron donation by traditional OER: developing efficient catalysts for water oxidation to promote H2 production; 2) electron donation by the oxidation of sacrificial agents: using sacrificial agents to assist H2 production; 3) electron donation by electrosynthesis reaction: achieving electrosynthesis in parallel with cathodic H2 production. Present challenges and related prospects will also be discussed, hopefully to benefit the further progress of electrocatalytic H2 generation.

and environmental problems caused by the consumption of fossil fuels. [2] Conventional electrocatalytic systems, which are usually driven by an external electric supply and focus on producing a singletarget chemical, cannot meet the current demands of human society. [3] Therefore, novel electrocatalytic systems, especially co-electrocatalysis and self-powered electrocatalysis, have been designed to produce higher-value-added chemicals yields with a lower consumption of energy.Our group has previously reported the co-electrocatalytic conversions of H 2 O and glycerol, [4] and CO 2 and methanol, [5] which require an external power supply; however, their electrical energy consumption is significantly reduced, and the final products are value-added compounds. Comparatively, self-powered systems such as lithium-carbon, [6] Zn-H 2 O, [7] Zn-NO 3 -, [8] and hydrazine-H 2 O, [9] have also been reported using sacrificial metal anodes. Although self-powered systems have been considered an efficient method to produce high-value chemicals, two major drawbacks are associated with the applications of currently available SPSs: i) strong acidic and/or alkaline electrolytes are used, thus posing a safety risk to the operators, and ii) anodes are consumed without any value-added chemicals being produced. [10] Herein, we report a general and efficient self-co-electrolysis system (SCES) for the co-production of high-value chemicals at both electrodes in a neutral phosphate buffer solution (PBS) that does not require external power. This method assimilates the favorable chemical production by co-electrocatalysis and the self-energy supply of SPSs in one system. Additionally, it minimizes both safety and environmental concerns. We have chosen to use Zn as the anode in our system.Zn is abundant in the earth and is relatively inexpensive. It has a moderate equilibrium potential (−0.76 V), which features both high safety and high electrochemical performance under aqueous conditions. H 2 can be easily generated by sacrificing Zn in acidic or alkaline solutions; however, neutral media pose fewer safety risks; nonetheless, the reaction remains challenging owing to its sluggish kinetics and the low-value counterpart product of ZnO. To the best of our knowledge, there are no reports based on electrochemical Zn-H 2 O assemblies that employ neutral electrolytes. We hypothesized that a commercial Zn-H 2 O electrochemical configuration for efficient HER using neutral electrolytes under ambient conditions should meet twoThe spontaneous reaction between Zn and H 2 O is of critical importance and could plausibly be used to produce H 2 gas, especially under neutral conditions. However, this reaction has long been overlooked owing to its sluggish kinetics and Zn consumption. Herein, a unique self-co-electrolysis system (SCES) is reported, which uses a Zn anode, a CoP-based catalytic cathode, and a neutral phosphate buffer solution (PBS) as the electrolyte. In this SCES, Zn is not only a sacrificial anode but also an important precursor of highvalue...

Electrocatalytic nitrate reduction reaction (NO 3 − RR) has been considered a promising technology to produce ammonia but is inhibited by poor electrocatalytic performances. Therefore, the development of efficient electrocatalysts and investigation of corresponding reaction mechanisms are critically important. Herein, an efficient dendritic Cu 2 O/Cu grown on Cu foam (D-Cu 2 O/Cu/CF) has been synthesized by a facile electrodeposition method, and the synergetic effect of Cu and Cu + in NO 3 − RR has been investigated. In situ and ex situ data testify the synergetic effect clearly that Cu sites are responsible for the beginning of nitrate conversion to nitrite, while Cu + sites are the active center for subsequent nitrite reduction to ammonia. In addition, in situ-generated active Cu + sites further enhance the catalytic performances. Therefore, an extraordinarily high nitrate removal rate of 98.9% together with a relatively high ammonia yield rate of 11.2 mg h −1 cm −2 can be obtained in electrolytes containing 90 ppm of nitrate.

H2 production via water electrolysis is of great significance in clean energy production, which, however, suffers from the sluggish kinetics of the anodic oxygen evolution reaction (OER). Moreover, the anode product, O2, which is of rather low value, may lead to dangerous explosions and the generation of membrane‐degrading reactive oxygen species. Herein, to address these issues of electrocatalytic H2 production, we summarize the most recent advances in three stages based on the benefit increments and various electron donation routes, which are: 1) electron donation by traditional OER: developing efficient catalysts for water oxidation to promote H2 production; 2) electron donation by the oxidation of sacrificial agents: using sacrificial agents to assist H2 production; 3) electron donation by electrosynthesis reaction: achieving electrosynthesis in parallel with cathodic H2 production. Present challenges and related prospects will also be discussed, hopefully to benefit the further progress of electrocatalytic H2 generation.

The electrochemical conversion of carbon dioxide into energy‐carrying compounds or value‐added chemicals is of great significance for diminishing the greenhouse effect and the efficient utilization of carbon‐dioxide emissions, but it suffers from the kinetically sluggish anodic oxygen evolution reaction (OER) and its less value‐added production of O2. We report a general strategy for efficient formic‐acid synthesis by a concurrent cathodic CO2 reduction and anodic partial methanol‐oxidation reaction (MOR) using mesoporous SnO2 grown on carbon cloth (mSnO2/CC) and CuO nanosheets grown on copper foam (CuONS/CF) as cathodic and anodic catalysts, respectively. Anodic CuONS/CF enables an extremely lowered potential of 1.47 V vs. RHE (100 mA cm−2), featuring a significantly enhanced electro‐activity in comparison to the OER. The cathodic mSnO2/CC shows a rather high Faraday efficiency of 81 % at 0.7 V vs. RHE for formic‐acid production from CO2. The established electrolyzer equipped with CuONS/CF at the anode and mSnO2/CC at the cathode requires a considerably low cell voltage of 0.93 V at 10 mA cm−2 for formic‐acid production at both sides.

Electrocatalytic hydrogen production under acidic conditions is of great importance for industrialization in comparison to that in alkaline media, which, unfortunately, still remains challenging due to the lack of earth-abundant, cost-effective and highly active anodic electrocatalysts that can be used durably under strongly acidic conditions.H ere we report an unexpected finding that manganese oxide,akind of common non-noble catalysts easily soluble in acidic solutions, can be applied as ah ighly efficient and extremely durable anodic electrocatalyst for hydrogen production from an acidic aqueous solution of alcohols.P articularly in ag lycerol solution, ap otential of as lowa s1 .36 V( vs.R HE) is needed at 10 mA cm À2 ,w hich is 270 mV lower than that of oxygen evolution reaction (OER), to oxidizeglycerol into value-added chemicals such as formic acid, without oxygen production. To our surprise,t he manganese oxide exhibits extremely high stability for electrocatalytic hydrogen production in coupling with glycerol oxidation for longer than 865 hours compared to shorter than 10 hfor OER. Moreover,the effect of the addition of glycerol on the electrochemical durability has been probed via in situ Raman spectroscopic analysis and density functional theory (DFT) calculations.T his work demonstrates that acidunstable metal oxide electrocatalysts can be used robustly in acidic media under the presence of certain substances for electrochemical purposes,such as hydrogen production.