Taking advantage of the self-assembling function of amino acids, cobaltalanine complexes are synthesized by straightforward process of chemical precipitation. Through a controllable calcination of the cobalt-alanine complexes, N-doped Co 3 O 4 nanostructures (N-Co 3 O 4 ) and N-doped CoO composites with amorphous carbon (N-CoO/C) are obtained. These N-doped cobalt oxide materials with novel porous nanostructures and minimal oxygen vacancies show a high and stable activity for the oxygen evolution reaction. Moreover, the influence of calcination temperature, electrolyte concentration, and electrode substrate to the reaction are compared and analyzed. The results of experiments and density functional theory calculations demonstrate that N-doping promotes the catalytic activity through improving electronic conductivity, increasing OH − adsorption strength, and accelerating reaction kinetics. Using a simple synthetic strategy, N-Co 3 O 4 reserves the structural advantages of micro/nanostructured complexes, showing exciting potential as a catalyst for the oxygen evolution reaction with good stability.

With the ever increasing demand for clean, sustainable energy, electrochemical supercapacitors with the advantages of high power density, high efficiency and long life expectancy have become one of the major devices for energy storage and power supply, and have found wide application in hybrid power sources, backup power sources, starting power for fuel cells and burst-power generation in electronic devices.

N,S co-doped 3D mesoporous carbon–Co3Si2O5(OH)4 composites are employed as electrodes together with activated carbon for pseudo-solid-state flexible electrochemical capacitors, which show a high performance.

are named as electrochemical double layer capacitors (EDLCs) and pseudocapacitors. [13][14][15] EDLCs produce capacitance from the electrostatic charge which is accumulated at electrode/electrolyte interface producing the electrostatic charge separation; besides, the ordinary electrode materials are carbon materials, such as activated carbon, graphene, and carbon nanotubes (Figure 1a). [16,17] Carbon-based materials, such as activated carbon, [18][19][20] carbon nanofibers, [21,22] carbon nanotubes, [23][24][25] and graphene, [26][27][28][29][30] present high surface areas, good electronic conductivities, and chemical stabilities. The other approach is pseudocapacitor, in which faradic processes are generated due to electroactive species (Figure 1b). The active materials in the electroactive species contain hydroxides, transition metal oxides, and conducting polymers. [31][32][33][34] Specifically, conducting polymers present high specific capacitance; however, their weaknesses are of high cost and poor cycling stability roots in their low conductivity. Beyond that, pseudocapacitive transition metal oxides serve as admirable supercapacitor electrodes. [35][36][37] Nonetheless, the poor cycling life and low energy density impose restrictions on their practical applications, especially for two electrode supercapacitor thus encouraged us to design new electrode materials from these pseudocapacitive metal oxides. In the meanwhile, the comprehensiveness of transition metal oxides/hydroxides and carbon-based materials led to high quality of performance and arose significant attention. [34,38,39] For example, on account of the superior pseudocapacitive performance, RuO 2 has attracted increasing attention, although it exhibits a limitation in practical applications due to its high cost. [40,41] Due to the fact, RuO 2 ·xH 2 O/carbon nanofiber composites obtained by Pico et al. present high specific capacitance and long cycle life. [42] Typically, for high-performance SCs, hollow structures were investigated to increase their active surface areas and porosity for efficient transportation. [43][44][45] In addition, hollow micro/nanostructured materials have proven their valuable applications in energy storage system (Li-ion batteries [46][47][48][49][50] and SCs [51][52][53][54] ) resulting from their shell functionality [55] and novel interior geometry. Especially, the hollow nanostructure presents a competent link between electrode materials and the electrolyte, which also can improve the electrochemical performance. [56] The hollow structure also possesses far more cavities, which works as an ''ion reservoir'' and ample room, in favor of lattice expansion. [57,58] So far, it is common to obtain hollow structures via template-method and water/oil/water (W/O/W) Electrochemical capacitors (supercapacitors, SCs), have been deemed to be one of the most promising powerful electrochemical energy storage devices, owing to that SCs have long cycle lives, high power densities, and fast recharge capabilities. Transition metal oxid...

The as-prepared AuNPs@silica/FFP (GSP) membrane displays strong and reusable performance for highly efficient water desalination and decontamination.