First-Principle Framework for Total Charging Energies in Electrocatalytic Materials and Charge-Responsive Molecular Binding at Gas–Surface Interfaces

Abstract

Heterogeneous charge-responsive molecular binding to electrocatalytic materials has been predicted in several recent works. This phenomenon offers the possibility of using voltage to manipulate the strength of the binding interaction with the target gas molecule and thereby circumvent thermochemistry constraints, which inhibit achieving both efficient binding and facile release of important targets such as CO2 and H2. Stability analysis of such charge-induced molecular adsorption has been beyond the reach of existing first-principle approaches. Here, we draw on concepts from semiconductor physics and density functional theory to develop a first principle theoretical approach that allows calculation of the change in total energy of the supercell due to charging. Coupled with the calculated adsorption energy of gas molecules at any given charge, this allows a complete description of the energetics of the charge-induced molecular adsorption process. Using CO2 molecular adsorption onto negatively charged h-BN (wide-gap semiconductor) and g-C4N3 (half metal) as example cases, our analysis reveals that - while adsorption is exothermic after charge is introduced - the overall adsorption processes are not intrinsically spontaneous due to the energetic cost of charging the materials. The energies needed to overcome the barriers of these processes are 2.10 and 0.43 eV for h-BN and g-C4N3, respectively. This first principle approach opens up new pathways for a more complete description of charge-induced and electrocatalytic processes.

Charge‐ and Electric‐Field‐Controlled Switchable Carbon Dioxide Capture and Gas Separation on a C2N Monolayer

“…[9,11] However, the switching on/off of the charge states or electric fields of these adsorbents to control the processo f CO 2 capture/releaseh as some disadvantages.O ne is that the modification of charge states or the application of an electric field consumes al arge amount of energy when using adsorbents with aw ide band gap (the band gap of aB Ns heet is 5.8 eV). [12] Theo ther is that the fabrication of the doped materialsi sd ifficult. Therefore, the search for new materials with ah igh stability and to which extra charge or external electric fields can be applied easily through electrochemical methodsi sachallenging task.…”

Can Charge‐Modulated Metal‐Organic Frameworks Achieve High‐Performance CO2 Capture and Separation over H2, N2, and CH4?

“…These values are lower than those of previous charge‐modulated CO 2 capture materials, such as Fe−N−C nanosheets (5.1 GJ ton −1 ), [40] C 3 N (10.6 GJ ton −1 ), [41] C 2 N (10.1 GJ ton −1 ), [20] and borophene (6.1 GJ ton −1 ) [18] . The charging energy is considered to further evaluate the performance of Co‐HAB and Ni‐HAB as charge‐modulated CO 2 capture materials [42] . The total charging energies in Co‐HAB and Ni‐HAB are calculated to be 1.650 and 2.941 eV when injecting 1.0 and 1.5 e − , respectively, which are comparable to those of previously reported materials, such as h ‐BN (9.62 eV), g‐C 4 N 3 (1.09 eV), graphene (5.54 eV), and g‐C 3 N 4 (4.36 eV) [42] .…”

“…The charging energy is considered to further evaluate the performance of Co‐HAB and Ni‐HAB as charge‐modulated CO 2 capture materials [42] . The total charging energies in Co‐HAB and Ni‐HAB are calculated to be 1.650 and 2.941 eV when injecting 1.0 and 1.5 e − , respectively, which are comparable to those of previously reported materials, such as h ‐BN (9.62 eV), g‐C 4 N 3 (1.09 eV), graphene (5.54 eV), and g‐C 3 N 4 (4.36 eV) [42] . In a word, the CO 2 adsorption/desorption on Co‐HAB and Ni‐HAB can be easily controlled by injecting/rejecting charges, and the low energy consumption renders them to be excellent charge‐modulated CO 2 capture materials.…”

First‐Principles Study of Electrocatalytically Reversible CO2 Capture on Graphene‐like C3N

“…[42][43][44] Based on the extremely narrow bandgap (0.39 eV) of C 3 N, CO 2 capture on C 3 N through the electrochemical methods will be more feasible than that of C 2 N. [41,45] So, in the following parts, we will investigate three important gas mixtures, namely, postcombustion gas mixture (mainly CO 2 /N 2 ), precombustion gas mixture (predominantly-CO 2 /H 2 ), and nature gas sweetening gas mixture (CO 2 /CH 4 ), adsorption on C 3 N with the strategies of introducing charge and electric field. [42][43][44] Based on the extremely narrow bandgap (0.39 eV) of C 3 N, CO 2 capture on C 3 N through the electrochemical methods will be more feasible than that of C 2 N. [41,45] So, in the following parts, we will investigate three important gas mixtures, namely, postcombustion gas mixture (mainly CO 2 /N 2 ), precombustion gas mixture (predominantly-CO 2 /H 2 ), and nature gas sweetening gas mixture (CO 2 /CH 4 ), adsorption on C 3 N with the strategies of introducing charge and electric field.…”

“…Recently, we have also reported CO 2 capture and hydrogen storage controlled by electrochemical methods on C 2 N (with band gap of 1.70 eV). [42][43][44] Based on the extremely narrow bandgap (0.39 eV) of C 3 N, CO 2 capture on C 3 N through the electrochemical methods will be more feasible than that of C 2 N. [41,45] So, in the following parts, we will investigate three important gas mixtures, namely, postcombustion gas mixture (mainly CO 2 /N 2 ), precombustion gas mixture (predominantly-CO 2 /H 2 ), and nature gas sweetening gas mixture (CO 2 /CH 4 ), adsorption on C 3 N with the strategies of introducing charge and electric field. The investigation will provide useful information to experimental researchers for searching advanced materials for reversible capture CO 2 from the gas mixtures.…”