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The synergistic effect between metals is of great significance for improving the performance of materials, but the mechanism of synergistic catalytic of bimetallic has rarely been reported in the hydrolysis of sodium borohydride (NaBH 4 , SB). In this paper, a flower shaped Co 2 FeO 4 catalyst with high catalytic performance was selected from a series of Co x M 3-x O 4 (M = Fe, Ni, Cu) catalysts by controlling the composition. Based on the results of XPS characterization and density functional theory (DFT) calculation, the influence of component control on catalytic performance was discussed and explained from the perspective of electronic structure, and the "valence band center" and "D-band center" descriptors were introduced into the SB hydrolysis reaction. The simulation analysis results showed that the synergistic effect between Co–Fe elements resulted in the smallest center shift of the D band, the smallest binding energy of the hydrolysis reaction, and the best promoting effect on the electronic structure, manifested as the best catalytic performance. The calculation results were consistent with the XPS characterization results and the experimental results of hydrolysis performance testing, revealing the principle of bimetallic synergistic effect on catalytic performance. The synergistic effect between metals is of great significance for improving the performance of materials, but the mechanism of synergistic catalytic of bimetallic has rarely been reported in the hydrolysis of sodium borohydride (NaBH 4 , SB). In this paper, a flower shaped Co 2 FeO 4 catalyst with high catalytic performance was selected from a series of Co x M 3-x O 4 (M = Fe, Ni, Cu) catalysts by controlling the composition. Based on the results of XPS characterization and density functional theory (DFT) calculation, the influence of component control on catalytic performance was discussed and explained from the perspective of electronic structure, and the "valence band center" and "D-band center" descriptors were introduced into the SB hydrolysis reaction. The simulation analysis results showed that the synergistic effect between Co–Fe elements resulted in the smallest center shift of the D band, the smallest binding energy of the hydrolysis reaction, and the best promoting effect on the electronic structure, manifested as the best catalytic performance. The calculation results were consistent with the XPS characterization results and the experimental results of hydrolysis performance testing, revealing the principle of bimetallic synergistic effect on catalytic performance. [Display omitted] • Flower-like Co 2 FeO 4 showed the best catalytic performance. • The "D-band center" and "valence -band center" of Co 2 MO 4 were studied. • Composition and electronic control improve the catalytic performance of Co 2 MO 4. • The adsorption configuration of H 2 O on the Co 2 MO 4 (311) surface was studied. [ABSTRACT FROM AUTHOR]

Strategies for changing the conductivity of Li 2 CO 3 is introduced into the fabrication of Li-CO 2 battery. Benefitting from the favorable hierarchical architecture constructed (CPM-MnO 2), facile charge transfer occurs between catalytic surface and Li 2 CO 3 by –OH⋯O hydrogen bonds improves the metallicity of Li 2 CO 3 , facilitating the formation/decomposition of Li 2 CO 3 and bestowing an ultra-long-term stability of 1087 cycles (4348 h). Taking into account its simplicity, scalable character and outstanding performance, this hierarchical composite electrode paves an effective trajectory for the future development of highly efficient cathodes for durable metal-CO 2 batteries. [Display omitted] • Excellent hierarchical structure of MXene and MnO 2 on carbon paper was fabricated. • Enriched charge transfer occurred on MXene and the MnO 2 by OH⋯O hydrogen bonding. • The prepared batteries showed an ultra-long cycle lifetime and low overpotential. • The optimized electronic structure can improve the metallicity of Li 2 CO 3. • The accelerated decomposition of discharge products promoted CRR and CER kinetics. Lithium-CO 2 batteries are recognized as an essential strategy for efficient carbon sequestration and energy storage to achieve carbon neutrality. Their cycle-ability and polarization voltage, however, are hindered by high decomposition voltage (≈4.3–4.5 V) of insulating Li 2 CO 3. Herein, we report a significant advance toward the rational design of self-supporting and ultra-long cycle lifetime cathode for Li-CO 2 batteries, dependence on a favorable hierarchical architecture and rich charge transfer constructed by homogeneously distributed MnO 2 nanoplates rooted in the MXene surface supported by carbon paper. Detailedly, it exhibits impressive ultra-long-term stability of 1087 cycles (4348 h) with a low polarization gap (≈ 0.47 V) at a high current of 200 μA cm−2, which is outperformed by all the liquid electrolyte-based Li-CO2 batteries reported previously. Electronic structure analysis reveals that facile charge transfer occurs between catalytic surface and Li 2 CO 3 , springing from the –OH functional group (in MXene) to MnO 2 by –OH⋯O hydrogen bonds, which acts as charge transfer channels, improving the metallicity of Li 2 CO 3 and facilitating its decomposition and extending battery cyclability. This work paves an effective trajectory for the future development of highly efficient cathodes for durable metal-CO 2 batteries. [ABSTRACT FROM AUTHOR]

Improving the catalytic activity and long-term stability of catalysts have always been the goal of its application. The structure stability and good electrical conductivity of catalysts are the key to OER performance, which have been challenge for application of catalysts. In the paper, we designed an in-situ growth of hierarchical core-shell structure CuMn 0.5 Co 2 O 4 @CC with superior conductivity directly as the catalytic electrode for improved OER performance. The well-standing CuMn 0.5 Co 2 O 4 nanoneedles with mesoporous structure entirely encapsulated on the carbon fibers, exposing a large special surface area and structural stability, while carbon fibers improved its electrical conductivity. Meanwhile, the richer oxygen vacancies and self-regulating electronic structure by the diversification of the metal oxidation state in the catalyst would promote the OER activity and stability. Benefitting from these merits, the requiring overpotential of CuMn 0.5 Co 2 O 4 @CC was 189 mV at the current density of 10 mA cm−2 and the Tafel slop value was 64.1 mV⋅dec−1, which was lower than that of CuMn 0.5 Co 2 O 4 //CC (η 10 = 337 mV and Tafel slop value of 113.9 mV⋅dec−1). In addition, the CuMn 0.5 Co 2 O 4 @CC had a competitive stability of with the current retention rate of 95.3 % after 1000 cycles. The present work provide a useful attempt to construct highly catalytic active and durably stable metal oxide composite catalysts. The synthesized CuMn 0.5 Co 2 O 4 @CC electrode exhibited the excellent OER activity (η 10 = 189 mV and Tafel slope of 64.1 mV⋅dec−1) and higher stability (the current retention rate of 95.3 % after 1000 cycles), which was attributed to the excellent conductivity of carbon fiber, the large surface area of active ingredients, and the regulated electronic structure with adjacent elements. [Display omitted] • The large special surface area and coupled with high structural stability for CuMn 0.5 Co 2 O 4 @CC catalyst. • The richer oxygen vacancies and self-regulating electronic structure promote the OER performance. • The improving OER activity and stability was attributed to the synergetic coupling effect between CC and CuMn 0.5 Co 2 O 4. • A lower overpotential of 189 mV, Tafel slop of 64.1 mV⋅dec−1, and the current density retention of 95.3 % were obtained. [ABSTRACT FROM AUTHOR]

Ethylene is an ideal CO2 product in an electrocatalytic CO2 reduction reaction (CO2RR) with high economic value. This paper synthesised Al-doped octahedral Cu2O (Al–Cu2O) nanocrystal by a simple wet chemical method. The selectivity of CO2RR products was improved by doping Al onto the surface of octahedral Cu2O. The Al–Cu2O was used as an efficient electrocatalyst for CO2RR with selective ethylene production. The Al–Cu2O exhibited a high % Faradic efficiency (FEC2H4) of 44.9% at −1.23 V (vs. RHE) in CO2 saturated 0.1 M KHCO3 electrolyte. Charge transfer from the Al atom to the Cu atom occurs after Al doping in Cu2O, optimizing the electronic structure and facilitating CO2RR to ethylene production. The DFT calculation showed that the Al–Cu2O catalyst could effectively reduce the adsorption energy of the *CHCOH intermediate and promote the mass transfer of charges, thus improving the FEC2H4. After Al doping into Cu2O, the center of d orbitals shift positively, which makes the d–band closer to the Fermi level. Furthermore, the density of electronic states increases due to the interaction between Cu atoms and intermediates, thus accelerating the electrochemical CO2 reduction process. This work proved that the metal doping strategy can effectively improve the catalytic properties of Cu2O, thus providing a useful way for CO2 cycling and green production of C2H4. [ABSTRACT FROM AUTHOR]

Functionalized MXenes have attracted great interest due to their unique electrical, magnetic, optical, and electrochemical properties. In this paper, the effect of interlayer coupling on the electronic structures of Ti 2 CO 2 MXenes is investigated by using density functional theory. Due to the interlayer coupling, the band structures of Ti 2 CO 2 nanosheet are split, generating an indirect band gap of 0.869 eV, which is smaller than that of Ti 2 CO 2 monolayer (1.044 eV). Biaxial strain can be used to achieve the transitions of direct-indirect-negative band gaps semiconductor. The interlayer interaction effectively inhibits the structural changes under stress, resulting that the band gap of nanosheet be adjusted in a large stress range. Furthermore, the change trend of imaginary part ε 2 of the dielectric function indicates that stress has an obvious regulatory effect on the optical transition. The different responses of monolayer and nanosheet under stress provides more choice for the optical devices of Ti 2 CO 2 MXenes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The activity of electrochemical CO 2 RR is boosted by modulating the electronic structure of Au. • Metal-support interaction (MSI) combined with CeO 2 and MWCNT activates Au. • Matched work function using CeO 2 and MWCNT modifies the electronic structure of Au. • MSI via heterostructure could increased the binding strength of CO 2 adsorption verified by CO 2 -TPD. • Au/CeO 2 /MWCNT exhibits excellent electrocatalytic performance for CO 2 RR. Electrochemical CO 2 reduction reaction (CO 2 RR) is a promising method to convert CO 2 into high value carbon products. For commercial applications, the energy efficiency of CO 2 RR needs enhancement. Designing superior electrocatalysts is important to increase energy efficiency. This paper reports that the catalytic properties of Au can be enhanced by metal-support interaction (MSI) through CeO 2 and a multi-walled carbon nanotube (MWCNT). A heterostructure for MSI is constructed by matching work function using CeO 2 and MWCNT to modify the electronic structure of Au via cascade electron transfer. Through MSI, the Au/CeO 2 /MWCNT heterostructure exhibits 4.2 times higher CO selectivity than Au/CB, and 1.6 times higher CO selectivity than Au/CeO 2 at 200 mA cm−2. As a result, the energy efficiency of CO production from CO 2 RR can be significantly increased using Au/CeO 2 /MWCNT. These findings show the importance of MSI in designing high-performance catalysts for CO 2 RR. [ABSTRACT FROM AUTHOR]

The van der Waals (vdW) heterostructure combining different 2D materials stimulates broad research interests. Novel chemical and electronic properties can be obtained via building vdW heterostructures. In this paper, the CO 2 adsorption properties of buckled honeycomb antimonene/graphene (hb -Sb/G) vdW heterostructure are examined by first-principles calculation, which provides theoretical insights into the enhanced electrocatalytic activity for CO 2 reduction of hb -Sb/G heterostructure reported in a recent experimental study. Furthermore, by applying in-plane biaxial strains, the tunable Schottky barrier and transition of contact property are observed. As compressive strain decreases or tensile strain increases, the catalytic activity of hb -Sb/G heterostructure is predicted to be enhanced as a result of the increased interlayer coupling. Our work reveals the origin of electrocatalytic activity of hb -Sb/G heterostructure for CO 2 reduction and proposes a strain engineering method to enhance its catalytic activity via tuning its electronic structure. This work uncovers promising applications of hb -Sb/G heterostructure in green energy and ultra-thin devices. • Uncover promising applications of hb -Sb/G heterostructure in ultra-thin devices. • Theoretically explain the experimentally reported CO 2 RR electrocatalytic activity enhancement of hb -Sb/G heterostructure. • Propose a strain engineering method to enhance the catalytic activity of 2D heterostructures. [ABSTRACT FROM AUTHOR]

• The paper introduces reticular materials for electrocatalytic reduction of CO 2. • The paper summarizes structural modulation to active sites of MOFs and COFs. • The paper highlights how to optimize electron transfer and mass transport. Catalytic conversion of excessively released greenhouse gas CO 2 faces grand challenges in terms of efficiency, selectivity, and stability. Reticular chemistry holds promises for the rational design of framework-based electrocatalysts crossing molecule-material level. We highlight the achievements in tailoring electronic structure and mass transport properties of CO 2 in framework materials, which have shown promising electrocatalytic CO 2 reduction performance. We also outline the challenges in the fundamental understanding of electrocatalytic reduction of CO 2 on framework materials, as well as heading to industrial utilization. [ABSTRACT FROM AUTHOR]

• Full characterization of NiII( tpa ) complexes gives information about its electronic structure which corelates with electrochemical behavior. • NiII( tpa ) complexes presented tunable redox potential for the NiII/NiI reduction. • NiII complex with more negative redox potential presented the high catalytic activity for CO 2 reduction. • Theoretical approach was useful for the analysis and description of electrochemical mechanisms. In this paper, we report the synthesis, characterization, as well as electrochemical, spectroelectrochemical, and density functional theory (DFT) calculations of a series of novel NiII complexes with a flexible tetradentate ligand, tris(2-pyridylmethyl)amine) ( tpa ). The complexes [NiII( tpa )(H 2 O)(MeCN)](BF 4) 2 , [NiII( tpa )(NO 3) 2 ], and [NiII( tpa )Cl 2 ] were studied for their ability to electrochemically reduce CO 2. These complexes were compared with the tris-chelate complex [Ni(bpy) 3 ](BF 4) 2 to understand the role of flexible tetradentate ligands containing a pyridinic ring in the electrochemical reduction of CO 2. Spectroelectrochemical experiments and theoretical studies were performed to rationalize the electrochemical reductions occurring and to predict the redox potential and pathway of CO 2 reduction. The electrochemical behavior of Ni(II) complexes with the ligand tris(2-pyridylmethyl)amine) was studied, in order to explore its ability to reduce electrochemically CO 2. Theoretical studies allowed to rationalize where the electrochemical reductions occur and predict redox potential and the pathway of CO 2 reduction. [Display omitted] [ABSTRACT FROM AUTHOR]

The van der Waals (vdW) heterostructures are constructed by stacking MoSe 2 on top of Zr 2 CO 2 MXene. Zr 2 CO 2 and MoSe 2 monolayers can form type II heterostructure, and the interfacial electronic states coupling between Zr 2 CO 2 and MoSe 2 is responsible for gap states. The effect of strain on the electronic structure and optical properties of Zr 2 CO 2 /MoS 2 heterostructure is investigated theoretically. The photocatalytic efficiency of Zr 2 CO 2 /MoSe 2 heterostructure is generally enhanced under strain through the analysis of effective mass. • Zr 2 CO 2 and MoSe 2 monolayers can form type II heterostructure. • Zr 2 CO 2 /MoSe 2 heterostructure undergoes the transition from semiconductor to metal under −4% strain. • The photocatalytic efficiency of Zr 2 CO 2 /MoSe 2 heterostructure is generally enhanced under strain. • The CBM and VBM under 0% strain are mainly from the Zr 2 CO 2 and MoSe 2 layers, respectively. Zr 2 CO 2 /MoS 2 heterostructure has attracted intensive attention because of its remarkable electronic and optoelectronic properties. In this paper, the van der Waals (vdW) heterostructures are constructed by stacking MoSe 2 on top of Zr 2 CO 2 MXene. The most stable stacking configuration is confirmed. Zr 2 CO 2 and MoSe 2 monolayers can form type II heterostructure, and the interfacial electronic states coupling between Zr 2 CO 2 and MoSe 2 is responsible for gap states. The effect of strain on the electronic structure and optical properties of Zr 2 CO 2 /MoS 2 heterostructure is investigated theoretically. The manner in which the strain modulates the band structure of Zr 2 CO 2 /MoS 2 heterostructure, including band gap, total/partial density of state, charge transfer is reported. The compressive and tensile strains can all result in the metallization of Zr 2 CO 2 /MoSe 2 heterostructure. The increasing amount of charge redistribution results in the transition from semiconductor to metal with the increasing compressive and tensile strain. The photocatalytic efficiency of Zr 2 CO 2 /MoSe 2 heterostructure is generally enhanced under strain. The effect of strain on optical properties is further explored. [ABSTRACT FROM AUTHOR]