Homopolymer bulk hydrogel of methacrylic acid was synthesized through a new single-step facile rout and used as a template for the fabrication of nickel (Ni) nanoparticles and as adsorbent to remove methylene blue (MB) and Rhodamine-6G (Rh-6G) from water. The Ni nanoparticles containing composite hydrogel was applied as catalyst for the degradation of a nitro compound. The carboxylic groups acted as highly efficient adsorption sites and their high degree was responsible for the removal of huge amounts of MB and Rh-6G from water. The maximum adsorption capacity of poly (methacrylic acid) hydrogel was 685 mg g−1 for MB and 1571 mg g−1 for Rh-6G. The adsorption data of MB was best fitted with Langmuir adsorption isotherm while that of Rh-6G with Temkin adsorption isotherm. Catalytic property of prepared hydrogel integrated with Ni nanoparticles was evaluated by using it as a catalyst for the degradation of 4-nitrophenol (4-NP). The apparent rate constant (kapp) observed in this study for the reduction of 4-NP was as high as 0.038 min−1. It was found that this catalyst system can be used repetitively with a slight decrease in catalytic activity.

No abstract

In the current era, the development of robust, eco‐friendly, and highly efficient electrocatalysts for generating hydrogen energy by water electrolysis has become a major challenge. This work explains the electrocatalytic performance of cost‐effective and amiable novel Ni‐BTC‐MWCNTs‐a as an active and effective electrocatalyst for OER in alkaline media. The catalytic activity of the nanocomposite is increased by heat treatment at 400°C temperature for 3 h. Systematic morphological and structural characterization studies of solvothermal synthesized materials were carried out by X‐ray powder diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy technique, scanning electron microscopy (SEM) analysis, and energy dispersive X‐ray spectroscopy (EDS) analysis techniques. Metal–organic framework (MOF)‐based composites exhibit improved catalytic performance owing to the synergistic effect of Nickel BTC MOF, MWCNTs support, and high‐temperature annealing (400°C). Among all as‐synthesized materials, the annealed Ni‐BTC‐MWCNT‐a exhibits admirable catalytic performance for oxygen evolution reaction (OER) at low value for over potential (η) 243 m V, small Tafel slope value 57 mV dec−1, smaller charge transfer resistance (0.274 Ω), and higher electrochemical active surface area (2000 cm2) with maximum durability for 23 h and utilized as auspicious alternate with excellent catalytic activity in water splitting OER process for producing hydrogen energy at large scale other than highly expensive electrocatalysts of Ir, Ru, Pd, and Pt oxides.

For manufacturing hydrogen energy via water splitting is the most important consequence for the revolution of a power disaster, and a vigorous and inexpensive electrocatalyst is the most challenging task. Herein, we report a unique MOF derived nanocomposite as an electrocatalyst (Ni-DA-MWCNTs-a) fabricated through the hydrothermal method, with ultrahigh functionality for the catalytic OER. The Ni-DA-MWCNTs-a synthesized electrocatalyst displays extremely porous morphology and is characterized by a number of different techniques. The fabricated nanocomposite demonstrates an extremely low overpotential of 267 mV, with a minimum Tafel slope of 61 mV dec −1 , considering the three-electron transfer process. Furthermore, the resultant nanocomposite displays the outstanding stability of 20 h and is confirmed by chronoamperometry. Hence, this work also exposed the valuable visions for the development of an inexpensive, effective, and useful electrocatalyst with an extremely small overpotential and good long-lasting durability for OER performance by utilizing 3D-MWCNTs resulting in a major alternative material derived from noble metals.