Impact of Crystal Types of AgFeO₂ Nanoparticles on the Peroxymonosulfate Activation in the Water

Abstract

A simple co-precipitation method was developed to synthesize AgFeO2 nanoparticles (NPs) with hexagonal 2H and 3R polytypes coexistence. The ratio of 2H and 3R types in AgFeO2 NPs were regulated by controlling the calcination temperature (300, 400, and 500 °C). Such AgFeO2 NPs were used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for the removal of Orange I (OI) in the water. External water conditions effects and the stability of AgFeO2 NPs were investigated. The catalytic performance of AgFeO2 NPs was found to be significantly enhanced with the increasing content of 2H-AgFeO2. 1O2, O2 •–, SO4 •–, and •OH were identified as the dominating reactive oxygen species (ROSs) participated in the catalytic process. The electron transfer of Ag0/Ag+ and Fe2+/Fe3+ cycles facilitated the decomposition of PMS to generate ROSs. The surface hydroxyl groups (−OH) were regarded as the catalytic active sites. The higher 2H-AgFeO2 content in AgFeO2 NPs promoted the concentration of surface hydroxyl groups (C –OH) and the reactivity of AgFeO2 NPs for PMS activation. Based on theoretical calculations, the 2H-AgFeO2 (004) plane with more Fe sites was more conducive to binding with the −OH compared to the 3R-AgFeO2 (012) plane, ascribed to the stronger adsorption energy and shorter Fe–O bond length between 2H-AgFeO2 and −OH.

Almost 100 % Peroxymonosulfate Conversion to Singlet Oxygen on Single‐Atom CoN2+2 Sites

“…2À + COH). [16] These results further indicated different reaction pathways and dominant ROS for PMS activation as catalyzed on CoN 2+2 active sites.…”

Facile Synthesis of AgFeO2‐Decorated CaCO3 with Enhanced Catalytic Activity in Activation of Peroxymonosulfate for Efficient Degradation of Organic Pollutants

“…A similar blueshift of the binding energy values of the Ag 3 d orbital can also be observed (Figure 6d), indicating the reduction of Ag(I) to Ag(0). [ 21 ] Approximately 1.1% of Fe(III) and 3.5% of Ag(I) were reduced to Fe(II) and Ag(0), respectively, during the catalytic process. These results suggest that both Fe(III)/Fe(II) and Ag(I)/Ag(0) redox pairs were involved in the degradation of RhB by the AgFeO 2 @CaCO 3 /PMS system.…”

“…The high 2H‐AgFeO 2 content in AgFeO 2 , as well as the electron transfer of Ag(0)/Ag(I) and Fe(II)/Fe(III) cycles, accelerates the utilization of PMS, thereby contributing to its high catalytic ability. [ 21 ] However, the resultant AgFeO 2 requires heating treatment, and its catalytic performance needs further enhancement for practical application.…”

AgFeO2 Delafosit Malzemelerin Sentez Koşulları, Kristal Yapısı, Morfolojisi ve OER Aktivitesi Arasındaki İlişki

“…Owing to this ability, the delafossites have recently started to receive attention in energy conversion applications as electro-catalyst or photo-catalyst [13][14][15]. Different delafossites such as CuCoO2, CuScO2, AgFeO2 were demonstrated to exhibit good electrochemical activity in KOH electrolyte [9,[16][17]. However, to our best knowledge, there is no report that links phase structure (3R vs. 2H) and morphology to OER activity in delafossite materials.…”