Cryptomelane nanorods coated with Ni ion doped Birnessite polymorphs as bifunctional efficient catalyst for the oxygen evolution reaction and degradation of organic contaminants

Abstract

The intelligent design or development of dual‐functional catalysts using non‐precious metals especially for the oxygen evolution reaction (OER) in sustainable energy systems and degradation of organic pollutants is still a difficult and a significant challenge. Furthermore, the development of these catalysts is of great importance in terms of energy security and solution of the environmental problems. To meet these requirements, herein, we describe the synthesis of a Ni‐ion doped Birnessite@Cryptomelane (Ni2+/B@Cr) hybrid structure as a bifunctional efficient catalyst for the OER in neutral media and degradation of dye pollutants. The Ni2+/B@Cr catalyst exhibited a sharp onset potential at 390 mV (vs. RHE) and achieved a current density of 1 mA cm−2 at a low ƞ of 430 mV with a Tafel slope of ~96 mV dec−1. The results of electrochemical impedance spectroscopy (EIS) studies indicated that Ni intercalation into birnessite layer and heterostructure of the hybrid electrocatalyst Ni2+/B@Cr increased the conductivity by lowering the resistance of charge transfer (Rct = 4.82 Ω) and oxygen evolution processes (ROER = 4.13 Ω). The durability assay identified Ni2+/B@Cr as stable electrocatalyst with 10% loss of activity after long‐term stability tests (10 h, under 500‐mV overpotential). In addition, the Ni2+/B@Cr achieved high (86.67 s−1 g−1) and rapid (173 s) catalytic performance for the reduction of methylene blue (MB). Overall, this paper presents a low‐cost production strategy for the design of highly efficient bifunctional catalysts, offering boosted electrocatalytic and degradation performance for water oxidation and organic dye contamination, respectively.

Binary NiCu oxide nanoparticles onto graphite as promoting nanocatalysts for ethanol electro‐oxidation process

“…However, the increased overpotential and inferior catalytic activity of bare nickel electrodes can impede the overall oxidation process. [21][22][23][24] In this respect, numerous efforts were proposed to enhance the measured catalytic efficiency of these nanocatalysts such as applying suitable polymeric supports for nanometallic species to increase their surface area (NiO/poly [3,4-ethylenedioxythiophene, poly (styrene sulfonic acid)/reduced graphene oxide] 25 and Ni/poly [diphenyl amine] 26 ) and alloying with other metals (Ni-Zn, 27 Ni-Fe, 28 Ni-Co, 29,30 Ni-Mn, 31,32 Ni-Cr, 33 and Ni-Mo 34,35 ) to modify the d-band structure of nickel that in turn significantly reduces the poisoning rates of fabricated nanocomposites during continuous operation. 36,37 Mohammadi et al 38 have examined the activity of RuNi nanoparticles inside metal-organic framework structure (MOF) onto carbon felt towards oxidizing ethanol molecules.…”

Peroxymonosulfate Activation by Cu–OMS-2 Nanofibers for Efficient Degradation of N-Containing Heterocycles in Aquatic Solution

“…It has abundant oxygen vacancies and mixed valence manganese ions [Mn­(II)/Mn­(III)/Mn­(IV)], which has good thermal stability, high content, low cost, easy preparation, environmental friendliness, and good selective adsorption and oxidation performance. , At present, a lot of works have been carried out on modified OMS-2 to obtain better catalytic performance, less aggregation, and less ion elution. Thus far, various OMS-2-based nanomaterials had been widely applied to activate PMS/PDS to eliminate POPs. − However, to date, there have been very limited investigations into NHC degradation by OMS-2-based nanomaterial activation of PMS/PDS, especially the simultaneous degradation of different types of NHCs in aquatic environments. There is an abundance of different types of contaminants in a natural aquatic environment, and whether the catalytic system can degrade different types of pollutants at the same time is very crucial.…”