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Electrochemical CO2 reduction (CO2R) powered by renewable energy to convert CO2 molecules into formate is of great interest. It is still challenging to develop an efficient CO2R catalyst with high ...

Electrochemical synthesis of hydrogen peroxide (H2O2) through O2 electroreduction is an attractive alternative to the currently used anthraquinone process, and highly desirable for green chemical industries and environmental remediation. However, it remains a great challenge to develop cost-effective and durable electrocatalysts. Hence, rational strategy for developing electrocatalyst materials to achieve highly efficient 2e− pathway oxygen reduction reaction (ORR) electrocatalysis is extremely important for in situ electrochemical synthesis of H2O2. In the present work, an economical activated graphite felt (AGF) material, following a simple and low-cost gaseous acetic acid activation method, is developed. With this activation process, the electrochemical performance of the AGF shows a great promotion for H2O2 production rate. Compared with raw graphite felt (RGF) material, the yield of H2O2 achieved on AGF is enhanced by several folds. The enhanced performance might be attributed to its specific pore structure, high content of defects and transformation of surface chemical bonds, which derives from the activation with gaseous acetic acid at high temperature. It is found that the factors responsible for the remarkable electrocatalytic performance of AGF1100 are: 1) the special pore structure, which offers large area for reaction, obtained through gaseous acetic acid activation process at high temperature; 2) high content of sp3 C bonds, defects, and oxygen-containing functional groups, which can act as active sites for oxygen adsorption or reduction during the electrocatalytic process.

Developing new strategy to further improve hydrogen evolution reaction (HER) performance of transition metal-based electrocatalysts is of high significance to accelerate commercial application of hydrogen energy. Here, HER activity is significantly enhanced through introducing crystal defects. The combined methods of heat and cool shock calcination, mask fiber templates as both reducing agent and carbon source were applied to synthesize microtube-like electrocatalysts composed of cross-linked carbon sheets and ultrafine Ni nanoparticles. The extensive active sites (edges, corners, steps, jaggies and strain) on the surface of Ni nanoparticles caused by grain surface, twin boundaries and stacking faults could synergically accelerate HER activity by optimizing adsorption capability of electrocatalysts and exposing atoms with high surface energy. Meanwhile, the defect-rich Ni nanoparticles wrapped by few-layer graphene are uniformly fixed on the conductive carbon network, which provides abundant diffusion channels for H2 and electrolyte, as well as effectively prevents Ni nanoparticles aggregation and avoids Ni grains being peeled off during long-term HER operation. As expected, the as-prepared electrocatalyst exhibits prominently improved electrocatalytic activity and admirable stability for HER. This work provides some innovatively technical insight in new-type catalysts development and defects engineering.

Identifying non-precious-metal catalysts with desirable overall performance for oxygen reduction reaction (ORR) in either acidic or basic media is still a bottleneck. Here, a hybrid material is reported, in which tungsten carbide (WC) and ferberite (FeWO4) are attached to the Fe and N dual-doped ordered mesoporous carbon (WC-FeWO4@FeN-OMC) as a superior performance catalyst for the ORR in either acidic or basic media. In comparison with the frequently used Pt/C ORR catalyst (20 wt. %), our hybrid materials exhibit comparable electrocatalytic activity mainly via a 4e ORR process, better stability, and total tolerance to methanol in either acidic or basic media. These advantages, especially the outstanding stability in acidic media, render the WC-FeWO4@FeN-OMC as a promising potential non-precious-metal ORR catalyst in practical fuel cell applications.

In the present work, the WC stability during the preparation of Pt@WC/OMC (Ordered Mesoporous Carbon) electrocatalysts, through a pulse microwave-assisted polyol method, is investigated by the aid of X-ray diffraction and thermogravimetric method. More precisely, OMC self-supported tungsten carbide (WC/OMC) is successfully synthesized by combing the hydrothermal process and a hard template method and its stability is step by step checked during the preparation process of the Pt@WC/OMC electrocatalyst by the pulse microwave-assisted polyol method. It is found that the strong alkaline and acid environment has a relatively small but not serious effect on the stability of WC. It is also found that in absence of Pt precursor, microwave irradiation itself also has a small effect on the stability of WC, while once Pt precursor is introduced into the system, more than half of the initial WC disappears or is oxidized. To avoid this process, Pt@WC/OMC-MM is obtained by mechanically mixing (MM) the as prepared WC/OMC and Pt@C. Moreover, the electrochemical results of methanol oxidation reaction show that the content of WC has an obvious effect on Pt's activity toward MOR, with the best performance in the case of Pt 20 WC 22 /OMC-MM.

Metal-Nx-C based materials have emerged as one of the most promising electrocatalysts for electrochemical reduction of carbon dioxide (ERCD). Co-based macrocyclic compounds have shown unique performance, however, of which the relationship between the ligands structure surrounding Co–N4 centers and reaction mechanism remains vague. To explore this issue, here, a series of Co-based macrocyclic compounds are elaborately chosen as model catalysts, including phthalocyanine cobalt (CoPc), cobalt (II) meso-Tetraphenylporphine (CoTp) and cobalt tetramethoxyphenylporphyrin (CoTop), which possess well-defined Co-N4 coordinated centers but different ligands structure surrounding Co-N4. Electrochemical measurements show that CoPc possesses higher activity and selectivity for CO with Faradaic efficiency (FE) above 62% at −0.7 V (vs. RHE) relative to those of CoTp and CoTop. Combining density functional theory (DFT) calculations, it can be further confirmed that CoPc is more favorable for ERCD to CO due to the rapid formation of key intermediate COOH* and the desorption of CO, demonstrating that the structure of ligands (phthalocyanine) surrounding Co-N4 plays a crucial role in the high CO selectivity. It can be anticipated that an exclusive strategy will pave a new avenue for further understanding the ERCD mechanism of Co-Nx-C catalysts.