Advanced hematite nanomaterials for newly emerging applications

Because of the combined merits of rich physicochemical properties, abundance, low toxicity, etc., hematite (α-Fe2O3), one of the most chemically stable compounds based on the transition metal element iron, is endowed with multifunctionalities and has steadily been a research hotspot for decades. Very recently, advanced α-Fe2O3 materials have also been developed for applications in some cutting-edge fields. To reflect this trend, the latest progress in developing α-Fe2O3 materials for newly emerging applications is reviewed with a particular focus on the relationship between composition/nanostructure-induced electronic structure modulation and practical performance. Moreover, perspectives on the critical challenges as well as opportunities for future development of diverse functionalities are also discussed. We believe that this timely review will not only stimulate further increasing interest in α-Fe2O3 materials but also provide a profound understanding and insight into the rational design of other materials based on transition metal elements for various applications.

Rational Design of Black Phosphorus-Based Direct Z-Scheme Photocatalysts for Overall Water Splitting: The Role of Defects

Black phosphorus (BP) has received increasing interest as a promising photocatalyst for water splitting. Nevertheless, exploring the underlying hydrogen evolution reaction (HER) mechanism and improving the water oxidizing ability remains an urgent task. Here, using first-principles calculations, we uncover the role of point defects in improving the HER activity of BP photocatalysts. We demonstrate that the defective phosphorene can be effectively activated by the photoinduced electrons under solar light, exhibiting high HER catalytic activity in a broad pH range (0-10). Besides, we propose that the direct Z-scheme in the defective BP/SnSe₂ heterobilayer is quite feasible for photocatalytic overall water splitting. This mechanism could be further verified based on the excited state dynamics method. The role of point defects in the photocatalytic mechanism provides useful insights for the development of BP photocatalysts.