Search

The electrolysis of water using renewable energy is a promising approach to developing a sustainable hydrogen-based economy. To improve the efficiency of this process, it will be necessary to develop highly active electrocatalysts that promote the oxygen evolution reaction (OER). In the present study, the OER activity of a nickel oxide electrocatalyst was dramatically improved following the addition of a diamine to the electrolyte solution during electrodeposition. Operando UV/vis absorption spectroscopy was used to assess a number of nickel catalysts containing various diamines and other organic compounds. The data indicate that Ni(II) complexes were formed with the diamines during electrodeposition. Consequently, the catalytic activity of these materials was enhanced based on increased concentrations of active reaction sites for the OER process. Ni K-edge X-ray absorption spectra showed that these catalysts were composed of γ-NiOOH with a Ni3.6+ valence state. The coordination of the diamine molecules to the γ-NiOOH produced structural distortion that contributed to improved OER activity. This structural distortion is likely the most important factor in enhancing the OER activity of inorganic–organic composite catalysts.

A lanthanum-modified zeolitic imidazolate framework (La/ZIF-8) was developed to produce glycerol carbonate using CO2 and glycerol as raw materials. La/ZIF-8 provides a high catalytic glycerol conversion efficiency owing to its surface-attached nanoclusters of La2O3, which can be viewed as La3+–O2− pairs that strengthen the Lewis basicity and acidity, and the large specific surface area of ZIF-8. The catalytic glycerol conversion and the yield of glycerol carbonate were 46.5% and 35.3%, respectively, using CH3CN as a dehydrating agent. With increase in the amount of CH3CN, the water molecules could react with CH3CN to reduce the selectivity. When an inorganic dehydrating agent, MgCO3, was used to physically adsorb and remove water molecules in the reaction, the selectivity of the reaction could be increased to over 95%, which is the highest ever reported. Reaction kinetics analysis also revealed that the activation energy of using MgCO3 (5.4 kJ mol−1) as a dehydrating agent is lower than that using CH3CN (7.8 kJ mol−1). Moreover, the La/ZIF-8 could be recycled and reused at least three times with high catalytic performance. This study provides an effective material with dual Lewis basicity and acidity for CO2/glycerol conversion and significantly improves the catalytic performance using an inorganic dehydrating agent.

An efficient method to monitor and control the secondary structures of globular proteins is developed by adsorption of proteins from a bulk solution onto an air–liquid interface. By controlling the concentration of a protein in the aqueous phase, as well as the attractive force exerted by the template layer, the adsorption of proteins can be classified into two stages according to the variation of surface pressure. In the first stage, the proteins adsorb as a single-molecular layer. The interface–molecule interactions induce a structural transition of the adsorbed proteins into a β-sheet conformation (α/β 10). The glucose sensing experiments demonstrate that GOx with α-helix conformation has a much higher sensitivity than β-sheet GOx, attributed to its lower charge transfer resistance at the GOx–electrolyte interface. The present study not only provides a new approach to monitor, control, and design protein conformations, but also raises the importance of adsorption states of proteins in performing bio-activities at bio-interfaces.