MXenes and their interfaces for the taming of carbon dioxide & nitrate: A critical review

Rapid industrialization and urban development release large amounts of toxic pollutants such as nitrate (NO3−) and CO2, which cause not only environmental issues but also offer reasons of sickness worldwide. Several methods have been devised to purify air and water in the past 2 decades but went futile because of high cost, low-performance, and cause secondary pollutants. Converting NO3− and CO2 photochemically and electrochemically into energy-rich molecules and agro-boosters is an innovative strategy that can help with environmental remediation and meet the world's growing energy needs. However, these approaches require highly active, selective, and long-lasting catalysts. In this context, researchers have studied several smart and multifunctional materials for the reduction of NO3− and CO2 pollutants into valuable chemicals. Among them, MXenes, a class of 2D materials composed of carbonitrides, carbides, and nitrides of transition metals, have gained attention because of their remarkable physico-chemical, mechanical, and electrochemical properties. However, quantization of MXenes for photo and electrocatalytic NO3− and CO2, reduction is required, and the lessons learned must be applied to future MXene-based materials. This article focuses primarily on the photocatalytic and electrocatalytic conversion of NO3− and CO2 to value-added products, highlighting MXene-based catalysts, reaction intermediates, links between the tuneable properties of MXenes and their catalytic activities, research hurdles, and future prospects.