Synthesis and characterization of S-Scheme NiMn2O4/g-C3N4 nanocomposites heterojunction photocatalyst for effective degradation of organic pollutants under visible light

Abstract

• Preparation of NiMn 2 O 4 /g-C 3 N 4 nanocomposites by an ultrasonic-assisted co-precipitation approach. • Investigation the impact of various amount of NiMn 2 O 4 on the structure of nanocomposites. • The highest degradation was obtained in the presence of 1 %NiMn 2 O 4 /g-C 3 N 4 over eriochrome black t (96.4 %) under visible light. • •O 2 ‒ radicals are the most active species in the degradation of eriochrome black t. • The higher rate constant ( k = 0.0241 min ‒1 ) corresponded to the highest performance (96.41 %) according to the kinetics investigation. This work reports the first steps in the preparation of nickel manganese oxide (NiMn 2 O 4 ) using an inexpensive and straightforward co-precipitation approach. Next, NiMn 2 O 4 /g-C 3 N 4 heterostructure with varying mass ratios are made using an ultrasonic-assisted co-precipitation process. Many methods, including XRD, FTIR, EDS, SEM, TEM, BET, VSM, and DRS, were used to characterize NiMn 2 O 4 and its nanocomposites. The photocatalytic activity of NiMn 2 O 4 , g-C 3 N 4 , and various NiMn 2 O 4 /g-C 3 N 4 nanocomposites was studied for the degradation of eriochrome black T (EB). This is the first time that NiMn 2 O 4 has been coupled with carbon nitride, demonstrating outstanding photocatalytic efficiency. The results showed that numerous factors influenced efficiency, including NiMn 2 O 4 content, catalyst content, and EB concentration. 1 %NiMn 2 O 4 /g-C 3 N 4 has the highest performance, which 30 mg of 1 %NiMn 2 O 4 /g-C 3 N 4 to degrade 96.41 % of 10 ppm EB in the acidic media. The scavenger experiments revealed that superoxide radicals played an important part in the photodegradation events. The kinetics investigation found that a higher rate constant ( k = 0.0241 min ‒1 ) corresponded to better efficiency (96.41 %).

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