Revealing the Mechanism of Pore Surface Structure in Adsorption of Trace Formaldehyde by Constructing Monolithic Carbon with Multiple Uniform Micropores and Surface Species

The development of three-dimensional (3D) adsorbents for the long-term removal of trace formaldehyde (HCHO) remains a challenge due to weak host–guest interactions. While doping with inorganic heteroatoms (e.g., O, N, P, S) has been widely explored, the impact of pore size and doping with inert metals/metal oxides on formaldehyde adsorption is still poorly understood. Herein, a series of novel monolithic carbons ( mono C- x ) featuring uniform micropore and mechanical robustness were prepared by carbonizing the zeolitic imidazolate framework monolith precursor. Among these, mono C-800, with a pore size of 0.7 nm and surface doping of ZnO x and N species, exhibits exceptional formaldehyde adsorption. This is achieved through strong electrostatic and coordination interactions, making it highly efficient in capturing trace formaldehyde molecules. As a physical adsorbent, mono C-800 is regenerable at mild temperatures without producing harmful byproducts, making it ideal for indoor air formaldehyde removal. The adsorption mechanism was explored via experimental verification and Grand Canonical Monte Carlo (GCMC) simulations, revealing the critical role of pore structure and surface species. This work offers valuable insights into designing and optimizing carbon-based adsorbents for trace formaldehyde remediation, providing potential solutions for improving indoor air quality.