Surface properties of carbon nitride materials used in photocatalytic systems for energy and environmental applications

The use of photocatalytic systems involving semiconductor materials for environmental and energy applications, such as water remediation and clean energy production, is highly significant. In line with this, a family of carbon-based polymeric materials known as carbon nitride (CNx) has emerged as a promising candidate for this purpose. Despite CNx's remarkable characteristics of performance, stability, and visible light responsiveness, its chemical inertness and poor surface properties hinder interfacial interactions, which are key to effective catalysis. This highlight reviews the literature focusing on the surface chemistry of CNx, especially its structural formation pathway, reactivity, and solvent interactions. It also explores recent advancements in the use of modified CNx for hydrogen production and arsenic remediation, offering recommendations for future material design improvements. We review what is known of the surface properties of carbon nitrides, increasingly popular photocatalysts, with a focus on hydrogen production and arsenic remediation.