B-Bridge Regulated Asymmetric Dual-Atomic Catalysts for Synergistically Enhanced Styrene Mineralization and CO2 Reduction

Abstract

Developing innovative resource utilization strategies to achieve sustainable recycling of waste-to-fuel is highly desirable, yet the design of cost-effective bifunctional catalysts with dual high-efficiency remains unexplored. While the Fenton-like reaction relies on enhancing peroxymonosulfate (PMS) adsorption and accelerating interfacial electron transfer to improve kinetic rates, CO2 reduction is constrained by sluggish kinetics and competing hydrogen evolution reaction. Herein, we construct a bifunctional catalyst (NiFe-BNC) featuring dual-atomic active sites by introducing boron atoms into a biomass-derived chitosan substrate rich in functional groups, which optimizes atomic coordination environments. In situ experiments and density functional theory calculations reveal that B-atom modulation facilitates carbon substrate defect enrichment, while the charge-tuning effect between metal sites and "boron electron bridge" optimizes PMS adsorption configurations. This synergistic effect facilitates the interfacial electron transfer and enhances the CO2 adsorption capacity of NiFe-BNC by 6 times that of NiFe-NC. The obtained NiFe-BNC exhibits significantly enhanced catalytic activity and selectivity, realizing 99% efficient degradation of volatile organic pollutants in the flowing phase within 2 h and stable mineralization exceeding 60%, while achieving a large current density of 1000 mA cm−2 and CO Faraday efficiency of 98% in the flow electrolytic cell. This work innovatively paves a new way for the rational design of cost-effective functional catalysts to achieve carbon cycle utilization.

1. Introduction

The dependence on fossil fuels leads to the generation of volatile organic pollutants (VOCs) and the accumulation of greenhouse gases [1, 2]. How to effectively degrade VOCs and further convert them into value-added chemical products. The innovative concept of “carbon closed-loop utilization” also provides new insights for simultaneously solving environmental problems and energy crises. The new advanced oxidation wet scrubbing process has been widely studied for VOCs removal due to its high efficiency, simple operation, and energy conservation [3, 4]. Different from the sequential batch reaction of the AOPs process for removing water pollutants, the continuous flow of VOCs passes through the liquid phase in the form of bubbles [5–7]. Therefore, highly active and stable catalysts are required for the efficient removal and deep mineralization of VOCs. Utilizing electrochemical CO2 reduction to convert into value-added chemicals is a valuable way to achieve carbon neutrality [8–10]. The important product CO can be applied to the Fischer–Tropsch synthesis process, and the selective generation of CO is also highly dependent on catalysts with high intrinsic activity [11–13]. In this regard, from the perspective of practical application, the development of bifunctional catalysts for converting waste gas into fuel is more attractive.

Recently, embedding atomically dispersed metal sites into carbon supports to form single-atom catalysts has attracted extensive attention from researchers due to its excellent atomic utilization efficiency and high selectivity [2, 14–16]. Carbonaceous materials with advantages such as large specific surface area and porous surface structures are regarded as ideal supports for constructing adsorption-catalysis materials [17, 18]. They are conducive to the rapid capture of gas molecules on the catalyst surface, which will greatly promote the adsorption of VOC gases and CO2 on the catalyst surface, as well as the contact and reaction between target VOCs and ROS [19]. The advanced oxidation process based on peroxymonosulfate (PMS) generates active species by breaking the O–O bond in PMS to attack pollutants. Meanwhile, the activation of PMS involves adsorption and interfacial electron transfer processes, and the electronic structure of metal atoms often affects the generation of radicals and the O–O bond breakage in PMS [20, 21]. The principle of the CO2 reduction process is that the catalyst can easily adsorb CO2 and firmly bind the COOH intermediate to effectively activate CO2, and CO has a weak interaction with the catalyst surface and is easy to desorb [22]. The reported M-N4 structure catalysts (Ni-NC and Fe-NC) have high energy barriers for the formation of the key intermediate product COOH and the desorption of C