Band Gap Engineering and Lattice Distortion for Synergetic Tuning Optical Properties of NaNbO3 toward Enhanced Piezo-photocatalytic Activity

Piezo-photocatalytic efficiency is severely constrained by the wide band gap and bad piezoelectric properties. Herein, La(Mn0.5Ni0.5)O3 was successfully introduced into NaNbO3 lattices (referred to as 0LMN, 0.05LMN, 0.10LMN, and 0.15LMN) through a water-based sol-gel method. The piezo-photocatalytic degradation ratio for Rhodamine B (RhB) is enhanced from 59.7% (0LMN) to 89.7% (0.10LMN) within 100 min, and the kinetic rate constant (k) is increased from 0.009 to 0.022 min-1. The enhanced performance is attributed to (i) the narrowed band gap (from 3.40 to 2.84 eV), which is conducive to the generation of photogenerated electrons and holes, and (ii) the enhanced piezoelectric properties, which can strengthen the piezoelectric polarization, thereby accelerating the separation of the photogenerated electrons and holes. And we also found that the synergetic effect of photocatalysis and piezocatalysis was superior to that of photocatalysis and piezocatalysis alone. This study could provide new perspectives for the reasonable construction of an efficient catalyst in the piezo-photocatalytic field.

Asymmetrical 1st reflection trend owing to metallization difference at ± Z-faces in indium tin oxide coated Fe-doped lithium niobate

The charges accumulated at the interface of indium tin oxide (ITO) and iron doped lithium niobate (LN) in an extremely thin layer because of semiconductor band alignment were analyzed with ab initio theory. The formation of 2D electron gas makes the interface metallic and the excitation of surface plasmon polaritons (SPPs) possible. In experiments, diametrically opposite trends of the very first reflection (VFR) on the ± Z-faces of ITO coated Fe-LN slabs were observed and associated with the differences in metallization and the photovoltaic charge accumulation there. Microscopically, the electric environments of the two ITO/LN interfaces differ greatly owing to spontaneous polarization and photovoltaic fields, which alter the band structures and band alignment, resulting in phase gratings with a π-shift difference recorded at the two interfaces. This affects the opposite energy coupling between the SPPs and laser beams and results in the dramatically opposite trends of VFR.

Schiff base complex conjugates of bovine serum albumin as artificial metalloenzymes for eco-friendly enantioselective sulfoxidation

Artificial metalloenzymes (BSA-ML) have been prepared by non-covalent insertion of transition metal Schiff-base complexes, ML (L = 2-hydroxynaphthalen-1-naphthaldehyde and 3,4-diaminobenzenesulfonic acid; M = Co, Mn, V, Fe, Cr), into bovine serum albumin (BSA) as the host protein and were characterized by UV-visible spectroscopy, ESI-TOF mass spectrometry and molecular docking studies. The catalytic activities of the BSA-ML in the selective oxidation of various prochiral sulfides in aqueous media, using H₂O₂ as oxidant, have been evaluated. During the optimization process, pH and the concentrations of catalyst and oxidant were found to have a remarkable influence on both yield and enantioselectivity. In certain cases, BSA-ML gave satisfactory results in the oxidation of organic sulfides to sulfoxides (up to 100% conversion, 100% chemoselectivity, 96% ee and 500 h⁻¹ turnover frequency).

Artificial metalloenzymes have been prepared by non-covalent insertion of transition metal Schiff-base complexes into bovine serum albumin as the host protein and were characterized by UV-visible spectroscopy, ESI-TOF mass spectrometry and molecular docking studies.