Cu or Rh-doped InSe monolayers for acid rain gas detection and capture: Insights from first-principles calculations

Acid rain gases, such as nitric oxide (NO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and sulfur trioxide (SO₃), pose serious environmental and health risks, highlighting the urgent need for efficient materials for their detection and capture. In this study, the gas sensing and adsorption properties of Cu- or Rh-doped InSe monolayers were systematically investigated using first-principles calculations. The results demonstrate that Cu doping significantly enhances the gas sensing sensitivity of InSe, particularly toward NO₂, SO₂, and SO₃, and maintains high sensitivity even at elevated temperatures. However, the prolonged recovery times of Cu-doped InSe limit its potential for real-time sensing, making it more suitable for gas scavenging applications. In contrast, Rh doping results in much stronger gas adsorption and ultra-long recovery times, rendering Rh-doped InSe a promising candidate for long-term gas capture and storage. Pristine InSe, with its weak interactions and low sensitivity, is unsuitable for gas sensing or scavenging. Overall, Cu-doped InSe is promising for gas detection, while Rh-doped InSe is better suited for long-term pollutant removal. These findings provide valuable insights for the design of multifunctional two-dimensional materials for environmental monitoring and pollutant control.