Two-dimensional (2D) materials have attracted attention for electrochemical energy storage applications because of their unique physical and chemical properties. However, the facile synthesis of thin 2D sheets remains a challenge. Herein, we demonstrate the formation of 3D assembly of thin Co–Al spinel sheets and carbon composite through a facile two steps process: hydrothermal synthesis of CoAl Layered double hydroxide (LDH) followed by heating of this LDH at high temperature to form CoAl2O4/C. This composite with a high specific surface area (SSA) of 102.7 m2 g–1 showed enhanced energy storage application. The CoAl2O4/C is capable of delivering specific capacitance of 1394 F g–1 under 1 A g–1 current density with 87% capacitance retention after 5000 cycles. For asymmetric supercapacitor (ASC), the CoAl2O4/C and activated carbon (AC) were used as cathode and anode, respectively. The device CoAl2O4/C//AC exhibits a high energy density of 76.34 W h kg–1 at a power density of 750.045 W kg–1 with good cyclic durability of 79% after 10 000 cycles. The improved electrochemical activity may be due to the 3D assembly of thin 2D Co–Al spinel nanosheets that allows easy electron and mass transport, high surface area, synergistic interaction among different components, etc. for which Co–Al spinel/C composite will find application in energy storage.

Hydrogen production from water electrolysis is of great interest for attaining sustainable clean energy storage and conversion, but the required working voltage (>1.23 V) in water splitting limits its applications in industrial expansion. Therefore, replacing the oxygen evolution reaction (OER) with a more favorable anodic oxidation reaction, which can provide more valuable products and less working voltage, will be of great significance for the upcoming expansion of hydrogen production in industrial applications. In this report, a two-dimensional (2D) amorphous sheet-like nickel oxide encapsulated on the nitrogendoped carbon (NiO x /CN x ) composite was synthesized for the urea oxidation reaction (UOR) and ethanol oxidation reaction (EOR). Remarkably, the catalyst shows 1.647, 1.378, and 1.354 V vs. reversible hydrogen electrode (RHE) potential at 10 mA/cm 2 current density for OER, UOR, and EOR, respectively, with good stability. The overall water, urea, and ethanol electrolyses of NiO x /CN x were carried out by coupling with commercial Pt/C as a cathode which shows only 1.626, 1.43, and 1.414 V cell potential at 20 mA/cm 2 current density. The catalyst also shows excellent chronopotentiometric and dynamic stability toward all the electrolyses. The high catalytic activity of NiO x /CN x may be attributed to the synergistic interaction between the support and materials, amorphous structure, 2D sheet-like morphology, porous structure, and high electrochemical surface area. This finding shows that NiO x /CN x nanosheets can replace noble metal-based catalysts for efficient anodic oxidation reactions.

A growing interest in the electrochemical conversion of biomass-derived compounds is attributed to the extremely high sustainability of this process, which has the potential to generate value-added products and renewable electricity from biowastes. The design and synthesis of a high surface area-interconnected porous network of metal nanomaterials are desirable for their application in the field of catalysis. In this work, the synthesis of the carbon-supported Ag nanoparticle aerogel (Ag–aerogel–CN x ) for electrocatalytic hydrogenation of 5-(hydroxymethyl)­furfural (HMF) is studied. The conversion of HMF to 2,5-hexanedione (HD) via ring opening using ambient pressure and temperature is demonstrated. Here, water is used as the hydrogen source and silver is used as the metal catalyst, which eliminates the use of H2 gas and the conventional method of hydrogenation that uses high pressure and temperature, which makes this reduction process more practical and efficient to produce HD. We investigated the most favorable potential for high Faradic efficiency and provided a plausible reduction path from HMF to HD. The production of HD is strongly dependent on the cathode potential and the nature of the electrolyte. The tuning of the cathodic potential can give high Faradic efficiency and suppress the other undesired byproducts like H2. A high Faradic efficiency of 78% and selectivity of 77% are observed for the conversion of HMF to HD on Ag–aerogel–CN x at −1.1 V versus Ag/AgCl in 0.5 M H2SO4. This direct six-electron reduction of HMF to HD can provide a new route to produce valuable intermediates from biomass.

Summary Design of advanced highly porous heteroatom‐doped carbon is desirable for their wide presence in applications like electrochemical energy storage systems, gas adsorption, and separation processes. In this work, porous nitrogen‐doped carbon was developed from ethylenediamine via an in situ self‐doping solvothermal process followed by pyrolysis and KOH activation under high temperature. Micropore‐rich nitrogen‐containing carbon materials were prepared through variation of the KOH/C ratio during activation and their electrochemical performance in alkaline electrolyte as well as CO2 sorption behaviour was evaluated. The porous carbon developed using KOH/C ratio of 2 delivered highest supercapacitor performance in 6 M KOH achieving high specific capacitance of 353 F g−1 with 1 A g−1 of current due to its high pore volume and micropore rich surface. The functionalized carbon delivered CO2 uptake capacities of 4.48 and 3.0 mmol g−1 under temperatures of 273 and 298 K, respectively, at 1 bar pressure with a good CO2/N2 selectivity of 20.58 and CO2/CH4 selectivity of 3.83. The existence of nitrogen functional groups, high surface area, and micropore‐rich porous structures may be the essential reasons behind superior electrode performance and CO2 capture capacity of the material. This work hopefully offers a simple development of N‐doped carbon for effective energy storage and CO2 adsorption systems.

Recently sodium-ion batteries have gained considerable attention over lithium-ion batteries because of their high earth abundance and low cost of sodium metal. Soft carbons with higher crystallinity and fewer defects compared to hard carbon are the preferred electrode material for tuning the reversible capacity of Na+ ion storage. In this work, we have successfully prepared N-doped soft carbons from formamide via a simple solvothermal process followed by pyrolysis at high temperatures. The presence of disorders and graphitic character was controlled via variation of the annealing temperature from 800 to 1400 °C. The prepared electrode material as an anode for Na+ storage shows a specific capacity of nearly 201 mA h g–1 under a current density of 20 mA g–1. The designed electrode also shows an excellent cyclic stability of 87% at 100 mA g–1 for 500 cycles. The enhanced performance of the optimized soft carbon may be ascribed to the synergistic interaction of graphitic and disordered domains and the doping of N into the soft carbon structure.

The design and synthesis of one-dimensional (1D) metal–organic frameworks (MOFs) with a high surface area are crucial for their potential usage in supercapacitor applications. 1D-Ni-MIL-77 MOF, synthesized by a one-step solvothermal method, is used here to investigate its activity in supercapacitor applications. High surface-to-volume ratios and short ion diffusion path lengths in 1D-structured nanomaterials result in high charge/discharge rates. 1D-Ni-MIL-77 MOF nanobelts show a high surface area of 93.48 m2 g–1 that gives ample active electrochemical sites. 1D-Ni-MIL-77 shows a specific capacitance (C) value of 1376 F g–1 under the current of 1 A g–1. Additionally, an asymmetric supercapacitor (ASC) was assembled by employing activated carbon as the negative electrode and a 1D-Ni-MIL-77 nanobelt as the positive electrode. With the assembled ASC, at a power density of 750 W kg–1, an energy density of 25 W h kg–1 was attained with a voltage ranging from 0 to 1.5 V. The cyclic durability of the ASC was examined, and it exhibited excellent retention of 95% of its initial capacitance after 5000 cycles.

Over past few years, layered double hydroxide (LDH) nanostructures attracted the attention of scientific community owing to their facile synthesis, interesting structure, morphology and has been promising in the fields...

In recent days, it has been reported that bimetallic electrocatalysts can increase the activity for electrochemical formate (HCOO − ) production during CO 2 reduction. However, they still have some apparent drawbacks such as poor selectivity and durability. In the current work, notable improvements in the electrochemical CO 2 reduction (CO 2 RR) to formate production were accomplished by incorporation of reduced graphene oxide (rGO) into nanostructured bimetallic CuSnO x electrocatalysts (Cu x SnO x /rGO). The interface-rich mixed crystalline−amorphous nanostructured Cu 0.33 SnO x /rGO nanocomposite is able to enhance the electrocatalytical activity, resulting in conversion of CO 2 to formate with lower overpotential of 590 mV vs RHE. The control experiments show that the presence of SnO x in the catalyst considerably increased electrocatalytic activity and product selectivity toward formate production. Further, the increased oxophilicity of the Cu 0.33 SnO x /rGO nanocomposite supports the plausible CO 2 reduction mechanism through the formation of bicarbonate intermediate, as demonstrated by CO stripping studies. The Cu 0.33 SnO x /rGO had maximum formate faradaic efficiency (80.62%) at lower potential of −0.69 V (RHE), which is 2.09 and 1.85 times better than those of CuSnO x /rGO and Cu 3 SnO x /rGO nanocomposites, respectively. The catalytic performance may be attributed to synergistic interaction, the presence of interfaces, higher electrochemical surface area, and the mixed crystalline−amorphous nature of Cu 0.33 SnO x /rGO nanocomposite. Thus, the obtained results gave rise to a practical method for boosting the activity and product selectivity of electrocatalysts for efficient CO 2 conversion.