Developing efficient bifunctional electrocatalysts based on inexpensive and earth-abundant materials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is essential for large-scale renewable energy storage and conversion processes but remains a major challenge. In this study, a bamboo-structured nitrogen-doped carbon nanotube coencapsulated with metallic cobalt and Mo2C nanoparticles (Co–Mo2C@NCNT) is designed and synthesized by a successive pyrolysis approach and demonstrated to be an efficient and stable bifunctional electrocatalyst for overall water splitting in alkaline medium. Attributing to favorable synergy interaction in composition and structure, the resultant Co–Mo2C@NCNT presents the superior performances toward HER, OER, and even overall water splitting in alkaline medium. To drive a current density of 10 mA cm–2, it needs only an overpotential of ∼186 and ∼377 mV for the electrocatalytic HER and OER, respectively, and a relatively low cell voltage (∼1.628 V) for overall water electrolysis. The present finding would open a new avenue to design and develop electocatalytically active multicomponent architectures for overall water splitting.
The thermal field effect effectively boosts water splitting electrocatalysis by lowering activation energy barriers and accelerating sluggish kinetics.
A synergetic architecture composed of nitrogen-doped carbon encapsulating cobalt and molybdenum carbide nanoparticles (CoxMoy@NC) presents excellent performance towards both HER and OER catalysis in alkaline medium.
Poly(N-methylaniline)/montmorillonite (PNMA/MMT) composite particles were obtained by using a simple in situ chemical oxidative polymerization method in hydrochloric acid solutions. Fourier transform infrared (FTIR) spectra, UV-visible absorption spectra and scanning electron microscopy (SEM) were carried out to characterize the as-prepared PNMA/MMT composite. On the basis of spectroscopy and morphology analysis, the probable polymerization mechanism was proposed. The potential application of PNMA/MMT composite for removal of heavy metal ions, such as Cu2+ and Zn2+, in aqueous solution was also investigated.
Cobalt nanoparticles embedded in porous N-rich carbon (PNC/Co) can perform as both active cathode and anode materials to drive the overall water splitting in alkaline media for simultaneous electrogeneration of hydrogen and oxygen gases.
The structural evolution of Ben clusters with n=5-9, the adsorption energy created by the Ben@H2O (n=5-9) complex, and the mechanism of the hydrogen evolution reaction of Ben+H2O (n=5-9) were all studied using a DFT calculation based on the PBE0-D3/Def2TZVP level. Excluding Be7 cluster, the global minimum structures of beryllium clusters with n=5–9 showed a higher point group pair formation. Be7 clusters' high point group symmetry is unstable. Be9@H2O released the greatest energy during the complex's creation (-1.45eV). Exothermic hydrogen evolution occurs in Ben+H2O (n=5–9), and all transition states, intermediate stages, and products have energies lower than the equilibrium constant (EC). More energy is released when an O-H bond in the Ben@H2O (n=5-9) complex is broken, and the energy release results in a change in the cluster structure, which is more pronounced in the Be7+H2O reaction. Interestingly, there are eight transition states in the Be6+H2O hydrogen evolution reaction, with the second O-H bond break requiring more energy than the first. There are only three transition states in the Be8+H2O hydrogen evolution reaction, and the reaction energy is the greatest (-4.13eV).
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
