This perspective focuses on the controversial issue of S-scheme electron transfer. It delves into the theoretical criteria and persistence of the driving force for S-scheme electron transfer.

Herein, Mg–Al layered double hydroxide (LDH) was firstly prepared by a water-in-oil microemulsion method and the prepared LDH sample was further calcined at different temperatures. The calcined LDH samples were carefully characterized using XRD, nitrogen adsorption, TEM, TGA, XPS, FTIR and zeta potential measurements. Calcined and uncalcined LDH samples were used as adsorbents to remove orange II (O-II) dye in water. Adsorption experiments indicated calcination temperatures had an obvious influence on the adsorption affinity of LDH, and the 500 °C calcined LDH sample (LDH-500) exhibited the maximum adsorption capacity of 602 mg g⁻¹ larger than that of LDH (224 mg g⁻¹). The pseudo-second-order model was the best kinetic model to describe O-II adsorbed on the surface of the adsorbent, and the dye adsorption was fitted well using the Langmuir model for the prepared samples. The adsorption mechanism of O-II dye onto the calcined and uncalcined LDHs samples was mainly related to electrostatic interaction between the anionic O-II molecules and positively charged surface of the adsorbents, and the slow intercalation of O-II into the layers of LDH and reconstruction of LDH-500.

Amorphous CuO is considered as an excellent cocatalyst, owing to its large surface area and superior conductivity compared with its crystalline counterpart. The current work demonstrates a facile method to prepare amorphous CuO, which is grown on the surface of graphitic carbon nitride (g-C₃N₄) and is then applied for the photocatalytic degradation of tetracycline hydrochloride. The prepared CuO/g-C₃N₄ composite shows higher photocatalytic activities compared with bare g-C₃N₄. Efficient charge transfer between g-C₃N₄ and CuO is confirmed by the photocurrent response spectra and photoluminescence spectra. This work provides a facile approach to prepare low-cost composites for the photocatalytic degradation of antibiotics to safeguard the environment.