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The coordinated configuration of atomic platinum (Pt) has always been identified as an active site with high intrinsic activity for hydrogen evolution reaction (HER). Herein, we purposely synthesize single vacancies in a carbon matrix (defective graphene) that can trap atomic Pt to form the Pt-C 3 configuration, which gives exceptionally high reactivity for HER in both acidic and alkaline solutions. The intrinsic activity of Pt-C 3 site is valued with a turnover frequency (TOF) of 26.41 s -1 and mass activity of 26.05 A g -1 at 100 mV, respectively, which are both nearly 18 times higher than those of commercial 20 wt % Pt/C. It is revealed that the optimal coordination Pt-C 3 has a stronger electron-capture ability and lower Gibbs free energy difference (Δ G ), resulting in promoting the reduction of adsorbed H + and the acceleration of H 2 desorption, thus exhibiting the extraordinary HER activity. This work provides a new insight on the unique coordinated configuration of dispersive atomic Pt in defective C matrix for superior HER performance.

Sub-nanometric Pd clusters on porous nanorods of CeO2 (PN-CeO2) with a high Pd dispersion of 73.6% exhibit the highest catalytic activity and best chemoselectivity for hydrogenation of nitroarenes to date. For hydrogenation of 4-nitrophenol, the catalysts yield a TOF of ∼44059 h(-1) and a chemoselectivity to 4-aminophenol of >99.9%. The superior catalytic performance can be attributed to a cooperative effect between the highly dispersed sub-nanometric Pd clusters for hydrogen activation and unique surface sites of PN-CeO2 with a high concentration of oxygen vacancy for an energetically and geometrically preferential adsorption of nitroarenes via nitro group. The high concentration of surface defects of PN-CeO2 and large Pd dispersion contribute to the enhanced catalytic activity for the hydrogenation reactions. The high chemoselectivity is mainly governed by the high Pd dispersion on the support. The catalysts also deliver high catalytic activity and selectivity for nitroaromatics with various reducible substituents into the corresponding aminoarenes.

The gas-phase reactions of sulfuric acid catalyzed hydrolysis of formaldehyde and formaldehyde with sulfuric acid and H2SO4···H2O complex are investigated employing the high-level quantum chemical calculations with M06-2X and CCSD(T) theoretical methods and the conventional transition state theory (CTST) with Eckart tunneling correction. The calculated results show that the energy barrier of hydrolysis of formaldehyde in gas phase is lowered to 6.09 kcal/mol from 38.04 kcal/mol, when the sulfuric acid is acted as a catalyst at the CCSD(T)/aug-cc-pv(T+d)z//M06-2X/6-311++G(3df,3pd) level of theory. Furthermore, the rate constant of the sulfuric acid catalyzed hydrolysis of formaldehyde combined with the concentrations of the species in the atmosphere demonstrates that the gas-phase hydrolysis of formaldehyde of sulfuric acid catalyst is feasible and could be of great importance for the sink of formaldehyde, which is in previously forbidden hydrolysis reaction. However, it is shown that the gas-phase reactions of formaldehyde with sulfuric acid and H2SO4···H2O complex lead to the formation of H2C(OH)OSO3H, which is of minor importance in the atmosphere.