The interaction of a water molecule with the (111) surfaces of stoichiometric and reduced ceria is investigated using first principle density functional theory with the inclusion of the on-site Coulomb interaction (DFT+U). It is found that on the stoichiometric ceria(111) surface, the water molecule is adsorbed spontaneously through single hydrogen bond configuration. In contrast, on the lightly reduced ceria(111), there exist both molecular adsorption (no-H-bond configuration) and dissociative adsorption (surface hydroxyl) modes. It is obvious that oxygen vacancies can enhance the interaction of water with the substrate. Phase diagrams for stoichiometric and reduced ceria(111) surfaces in equilibrium with water vapor in the complete range of experimentally accessible gas phase condition are calculated and discussed combining the DFT results and thermodynamics data using the ab initio atomistic thermodynamic method. We present a detailed analysis of the stability of the water-ceria system as a function of the ambient conditions, and focus on two important surface processes for water adsorption on the stoichiometric and on the lightly reduced surfaces, respectively.

Electrocatalytic two‐electron oxygen reduction has emerged as a promising alternative to the energy‐ and waste‐intensive anthraquinone process for distributed H2O2 production. This process, however, suffers from strong competition from the four‐electron pathway leading to low H2O2 selectivity. Herein, we report using a superhydrophilic O2‐entrapping electrocatalyst to enable superb two‐electron oxygen reduction electrocatalysis. The honeycomb carbon nanofibers (HCNFs) are robust and capable of achieving a high H2O2 selectivity of 97.3 %, much higher than that of its solid carbon nanofiber counterpart. Impressively, this catalyst achieves an ultrahigh mass activity of up to 220 A g−1, surpassing all other catalysts for two‐electron oxygen reduction reaction. The superhydrophilic porous carbon skeleton with rich oxygenated functional groups facilitates efficient electron transfer and better wetting of the catalyst by the electrolyte, and the interconnected cavities allow for more effective entrapping of the gas bubbles. The catalytic mechanism is further revealed by in situ Raman analysis and density functional theory calculations.

NiCo2O4 nanowire array on carbon cloth (NiCo2O4/CC) is proposed as a highly active electrocatalyst for ambient nitrate (NO3−) reduction to ammonia (NH3). In 0.1 m NaOH solution with 0.1 m NaNO3, such NiCo2O4/CC achieves a high Faradic efficiency of 99.0% and a large NH3 yield up to 973.2 µmol h−1 cm−2. The superior catalytic activity of NiCo2O4 comes from its half‐metal feature and optimized adsorption energy due to the existence of Ni in the crystal structure. A Zn‐NO3− battery with NiCo2O4/CC cathode also shows a record‐high battery performance.

Low-cost and efficient electrocatalysts are urgently required for the N 2 reduction reaction (NRR) to produce NH 3 under ambient conditions. By using first-principles calculation, we systematically investigated the NRR catalytic activity of the transition metal (TM, including Mn, Fe, Co, and Ni) monomer-, dimer-, and trimer-anchored graphdiyne (GDY) monolayers. It is shown that most of the TM monomer-and dimer-anchored GDY monolayers have enhanced NRR catalytic activity compared with the Ru(0001) stepped surface. Especially, the Co dimer-anchored GDY monolayer (Co 2 @GDY) exhibits the best NRR catalytic activity with the onset potential of −0.43 V and a high ability to suppress the competing hydrogen evolution reaction. The high NRR catalytic activity of Co 2 @GDY could be attributed to the localized electronic states near the Fermi level and the strong electron-donating ability of the GDY monolayer. Furthermore, an approximate linear trend between the predicted onset potential and the N adsorption energy is revealed, which may act as a simple descriptor for the intrinsic NRR catalytic activity of such catalysts. Our findings not only propose an efficient and low-cost double-atom catalyst for NRR but also provide a new clue for designing TM atomic catalysts based on GDY sheets for various electrocatalysis applications.