## 1 Introduction  
Peroxymonosulfate (PMS) is a representative sulfate-based oxidizing agent, characterized by its distinctive asymmetric structure (HO-SO\({}_{4}\)). In recent years, peroxymonosulfate-driven advanced oxidation processes (AOPs) have attracted significant attention due to their effectiveness in pollutant degradation and operational versatility [1, 2, 3, 4]. According to previous studies [5], PMS can be activated by ultraviolet (UV) [6], light [7], heat [8], ultrasound [9], basic particulate activated carbon [10], or transition metals (e.g., Fe, Co) [11, 12] to produce reactive sulfate radicals (SO\({}_{4}\)\({}^{-}\)). Among these activation methods, transition metal activation is the most common and efficient [13]. Among transition metals, iron-based catalysts have gained particular prominence due to their abundance, environmental compatibility, and cost-effectiveness. However, many iron-based catalysts face inherent challenges, such as a slow catalytic conversion rate from Fe(III) to Fe(II) and a significant pH dependency, which limits their effectiveness to acidic conditions [14]. In practical applications, PMS activation using iron-based catalysts under acidic conditions generates a radical reaction system based on the Fe(II)/Fe(III) cycle, which sequentially produces SO\({}_{4}\).- and hydroxyl radicals (-OH) [15]. While these radicals possess strong oxidative capabilities, their high reactivity also makes the system highly susceptible to interference from coexisting anions in wastewater [16]. This susceptibility leads to poor selectivity toward target pollutants, as the radicals readily react with inorganic salts, humic acid (HA), and other matrix components, resulting in reduced oxidant utilization efficiency and increased treatment costs in real-world wastewater applications [17]. To address these limitations, non-radical pathways have emerged as a promising alternative research focus. Among non-radical species in iron-based systems, high-valent iron-oxo species (\(\equiv\)Fe(IV)=O and \(\equiv\)Fe(V)=O) have been extensively studied [18]. Although the formation of high-valent iron-oxo species in iron-catalyzed systems was first reported decades ago, their application in PMS-based advanced oxidation processes (AOPs) has only recently gained momentum [19]. For instance, [PERSON] [20] synthesized Fe(II)-hexadecylchlorophthalate (FePcCl\({}_{16}\)) and demonstrated its ability to activate PMS under sunlight irradiation. This system effectively degraded carbamazepine, with minimal inhibition observed in the presence of common coexisting ions such as NaH\({}_{2}\)PO\({}_{4}\), NaHCO\({}_{3}\), MgSO\({}_{4}\), CaSO\({}_{4}\), and NaCl, which was attributed to the involvement of \(\equiv\)Fe\({}^{4*}\)=O. While iron-based catalysts capable of generating \(\equiv\)Fe(IV)=O have shown high catalytic efficiency across a broad pH range, most studies have predominantly focused on the initial pH of heterogeneous Fenton-like systems, often overlooking the influence of oxidants and reaction dynamics on system pH. This oversight has led to potentially misleading conclusions regarding pH independence [21]. In reality, PMS-induced formation of high-valent iron-oxo species remains constrained by pH conditions [22]. Consequently, the development of iron-based catalysts capable of truly overcoming pH limitations is critical for advancing AOP adoption in pollution control and for deepening our understanding of the underlying reaction mechanisms [23]. In this study, we synthesized Fe-Co-layered double hydroxides (FeCo-LDH) through a simple co-precipitation method by incorporating Co(OH)\({}_{2}\) into Fe(III)-based catalysts, facilitating the sequential production of high-valent iron-oxo species. By creating a neutral pH microenvironment, the amphiprotic Co(OH)\({}_{2}\) effectively extended the applicable pH range and mitigated the proton-assisted self-decomposition of \(\equiv\)Fe(IV)=O.