Recent progress in research and design concepts for the characterization, testing, and photocatalysts for nitrogen reduction reaction

Abstract

The reduction of molecular nitrogen (N2) to ammonia (NH3) under mild conditions is one of the most promising studies in the energy field due to the important role of NH3 in modern industry, production, and life. The photocatalytic reduction of N2 is expected to achieve clean and sustainable NH3 production by using clean solar energy. To date, the new photocatalysts for photocatalytic reduction of N2 to NH3 at room temperature and atmospheric pressure have not been fully developed. The major challenge is to achieve high light‐absorption efficiency, conversion efficiency, and stability of photocatalysts. Herein, the methods for measuring produced NH3 are compared, and the problems related to possible NH3 pollution in photocatalytic systems are mentioned to provide accurate ideas for measuring photocatalytic efficiency. The recent progress of nitrogen reduction reaction (NRR) photocatalysts at ambient temperature and pressure is summarized by introducing charge transfer, migration, and separation in photocatalytic NRR, which provides guidance for the selection of future photocatalyst selection. More importantly, we introduce the latest research strategies of photocatalysts in detail, which can guide the preparation and design of photocatalysts with high NRR activity.

Bi4O5Br2 Nanoflower and CdWO4 Nanorod Heterojunctions for Photocatalytic Synthesis of Ammonia

“…Photocatalysis, among various methods of artificial ammonia synthesis, utilizes inexhaustible solar energy as the driving energy to achieve N 2 -to-NH 3 conversion in a mild and clean way, rendering it a green, low-energy, and sustainable process with immense potential . Nevertheless, efficient photocatalytic N 2 fixation (PNF) applications pose a significant challenge due to the limited interfacial charge-transfer ability of semiconductor photocatalytic materials and the tendency of electron–hole pairs to recombine. , …”

“…1 Nevertheless, efficient photocatalytic N 2 fixation (PNF) applications pose a significant challenge due to the limited interfacial charge-transfer ability of semiconductor photocatalytic materials and the tendency of electron−hole pairs to recombine. 2,3 In order to address the aforementioned issues, scientists have devoted significant effort to developing highly efficient photocatalysts and elucidating the PNF mechanism. Among recent advances in PNF, semiconductor heterojunction materials have garnered considerable attention as a research hotspot.…”

Electrochemical Co-Production of Ammonia and Biodegradable Polymer Monomer Glycolic Acid via the Co-Electrolysis of Nitrate Wastewater and Waste Plastic

“…Therefore, as a green and sustainable solution, the use of electrocatalytic technology to upcycle polluting waste into high value-added chemicals is reliable. For example, the electroreduction process can convert NO 3 – into nontoxic nitrogen (N 2 ) or value-added ammonia (NH 3 ) under mild operating conditions. − Notably, compared to the useless N 2 , NH 3 is largely needed as a basic raw material for various chemicals and an important carbon-free energy carrier. − Meanwhile, the traditional NH 3 synthesis relies on the Haber–Bosch (H–B) process under high temperature and pressure operating conditions, resulting in serious environmental pollution and fossil energy consumption. − On the contrary, the electrochemical nitrate reduction reaction (NO 3 RR) can achieve value-added ammonia production while treating nitrate wastewater, which is a win–win environmentally friendly process. − In addition, the application of electrochemical oxidation in PET plastic waste upcycling can realize the conversion of EG from PET hydrolysate into value-added products (e.g., formate, glycolic acid (GA)). − However, most of the previous reports have focused on the conversion of EG to formate (C1), and less on C2 products. As a biodegradable material with high mechanical strength, high biocompatibility, and rapid degradation, polyglycolic acid (PGA) plastics are widely used in biomedical fields. , Nevertheless, limited GA production and high prices have resulted in insufficient PGA production.…”

A Calix[4]resorcinarene-Copper(II) Based Supramolecular Nanocapsule with Encapsulated Polyoxometalates for Enhanced Photocatalytic Activity

“…Photocatalysis is a rapidly evolving field that utilizes abundant and renewable solar energy sources to drive chemical reactions. , The primary obstacle in implementing this technology lies in the development of stable and high-efficient photocatalysts. , A variety of emerging semiconductor materials have been employed in photocatalysis, such as perovskite, carbon nitride, inorganic–organic hybrid, etc. − Among the various types of photocatalysts developed, inorganic–organic hybrid photocatalysts have been emerged as promising candidates for practical applications in photocatalysis. − These hybrid materials combine the advantageous properties of both inorganic and organic components, resulting in enhanced photocatalytic performance and increased versatility . Furthermore, inorganic–organic hybrid photocatalysts offer additional advantages, such as tunable properties and increased stability.…”