Production of ammonia is currently realized by the Haber–Bosch process, while electrochemical N2 fixation under ambient conditions is recognized as a promising green substitution in the near future. A lack of efficient electrocatalysts remains the primary hurdle for the initiation of potential electrocatalytic synthesis of ammonia. For cheaper metals, such as copper, limited progress has been made to date. In this work, we boost the N2 reduction reaction catalytic activity of Cu nanoparticles, which originally exhibited negligible N2 reduction reaction activity, via a local electron depletion effect. The electron-deficient Cu nanoparticles are brought in a Schottky rectifying contact with a polyimide support which retards the hydrogen evolution reaction process in basic electrolytes and facilitates the electrochemical N2 reduction reaction process under ambient aqueous conditions. This strategy of inducing electron deficiency provides new insight into the rational design of inexpensive N2 reduction reaction catalysts with high selectivity and activity.

Highly efficient fixation of CO 2 for the synthesis of useful organic carbonates has drawn much attention. The design of sustainable Lewis acid−base pairs, which has mainly relied on expensive organic ligands, is the key challenge in the activation of the substrate and CO 2 molecule. Here, we report the application of Mott−Schottky type nanohybrids composed of electron-deficient Cu and electron-rich N-doped carbon for CO 2 fixation. A ligand-free and additive-free method was used to boost the basicity of the carbon supports and the acidity of Cu by increasing the Schottky barrier at their boundary, mimicking the beneficial function of organic ligands acting as the Lewis acid and base in metal−organic frameworks (MOFs) or polymers and simultaneously avoiding the possible deactivation associated with the necessary stability of a heterogeneous catalyst. The optimal Cu/NC-0.5 catalyst exhibited a remarkably high turnover frequency (TOF) value of 615 h −1 at 80 °C, which is 10 times higher than that of the state-of-the-art metal-based heterogeneous catalysts in the literature.E xcessive emission of carbon dioxide has triggered numerous environmental problems. 1−3 Efficient reuse of CO 2 , which is an inexpensive, abundant, and nontoxic gas, is consistently considered a promising green chemistry process. 1−5 However, the high chemical stability of CO 2 makes its conversion difficult. 6 Current strategies for chemical fixation of CO 2 mainly focus on the conversion of CO 2 into useful organic carbonates, carbamates, ureas, and carboxylic acids. 7 Cycloaddition of CO 2 to epoxides is an important method for the synthesis of cyclic carbonates, 8,9 which are of great interest in industry as lithium battery electrolytes, nonprotic polar solvents, and monomers used for generating polycarbonates. 10 Recently, metal−organic frameworks (MOFs) 11,12 and porous ionic polymers 13 have been developed as reusable heterogeneous catalysts for the coupling reaction. This pioneering work has clearly demonstrated the importance of Lewis acid and/or base groups in facilitating the fixation of CO 2 and the activation of epoxides, 14−16 even though the expensive and complex method for the synthesis of MOF materials will limit their practical applications. In principle, electron-rich and electron-deficient areas at the boundary of a

Oxygen vacancies can help to capture oxygen-containing species and act as active centers for oxygen evolution reaction (OER). Unfortunately, effective methods for generating a high amount of oxygen vacancies on the surface of various nanocatalysts are rather limited. Here, we described an effective way to generate oxygen-vacancy-rich surface of transition metal oxides, exemplified with Co O , simply by constructing highly coupled interface of ultrafine Co O nanocrystals and metallic Ti. Impressively, the amounts of oxygen vacancy on the surface of Co O /Ti surpassed the reported values of the Co O modified even under highly critical conditions. The Co O /Ti electrode could provide a current density of 23 mA cm at an OER overpotential of 570 mV, low Tafel slope, and excellent durability in neutral medium. Because of the formation of a large amount of oxygen vacancies as the active centers for OER on the surface, the TOF value of the Co O @Ti electrode was optimized to be 3238 h at an OER overpotential of 570 mV, which is 380 times that of the state-of-the-art non-noble nanocatalysts in the literature.

A facile method was developed to fabricate nitrogen-doped graphene microtubes (N-GMT) with ultra-thin walls of 1-4 nm and large inner voids of 1-2 μm. The successful introduction of nitrogen dopants afforded N-GMT more active sites for significantly enhanced hydrogen evolution reaction (HER) activity, achieving a current density of 10 mA·cm -2 at overpotentials of 0.464 and 0.426 V vs. RHE in 0.1 and 6 M KOH solution, respectively. This HER performance surpassed that of the best metal-free catalyst reported in basic solution, further illustrating the great potential of N-GMT as an efficient HER catalyst for real applications in water splitting and chlor-alkali processes.

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