Covalent polymer functionalization of graphene/graphene oxide and its application as anticorrosion materials

Research on grapheme-polymer composites as the promising ion barrier materials to tackle the corrosion issue is rapidly developing and attracts interests from both academia and industry. In this minireview, we highlight the covalent functionalization of graphene and its derivatives such as graphene oxide (GO) with polymer brushes, and their application in anticorrosion within the last 3 years. There are some recent excellent reviews published on single layer graphene and graphene-based polymer composites for anticorrosion. However, the covalent functionalization of graphene and GO with polymer brushes for application in anticorrosion has not been addressed in those reviews. In this review, we describe first the current state of the art of covalent functionalization of graphene/GO with polymer brushes. We then discuss the application of pristine graphene as anticorrosion material and its drawbacks which can be overcome by graphene-based polymer composites. Afterwards, we discuss in detail the recent progress and development of covalent polymer functionalized graphene/GO as anticorrosion coatings, reported within the last 3 years. Finally, as perspective, we will briefly summarize the work on composites of polymers with other two-dimensional (2D) materials as anticorrosion coatings. Herein, hexagonal boron nitride, the most studied 2D materials after graphene, and Ti3C2Tx MXene which is the rising star of 2D transition metal carbide/nitride will be discussed

Ti₃C₂T_<i>x</i>MXene Polymer Composites for Anticorrosion:An Overview and Perspective

[Image: see text] As the most studied two-dimensional (2D) material from the MXene family, Ti(3)C(2)T(x) has constantly gained interest from academia and industry. Ti(3)C(2)T(x) MXene has the highest electrical conductivity (up to 24,000 S cm(–1)) and one of the highest stiffness values with a Young’s modulus of ∼ 334 GPa among water-dispersible conductive 2D materials. The negative surface charge of MXene helps to disperse it well in aqueous and other polar solvents. This solubility across a wide range of solvents, excellent interface interaction, tunable surface functionality, and stability with other organic/polymeric materials combined with the layered structure of Ti(3)C(2)T(x) MXene make it a promising material for anticorrosion coatings. While there are many reviews on Ti(3)C(2)T(x) MXene polymer composites for catalysis, flexible electronics, and energy storage, to our knowledge, no review has been published yet on MXenes’ anticorrosion applications. In this brief report, we summarize the current progress and the development of Ti(3)C(2)T(x) polymer composites for anticorrosion. We also provide an outlook and discussion on possible ways to improve the exploitation of Ti(3)C(2)T(x) polymer composites as anticorrosive materials. Finally, we provide a perspective beyond Ti(3)C(2)T(x) MXene composition for the development of future anticorrosion coatings

Electrocatalytic reduction of NO3- on palladium/copper electrodes

The reduction of NO3- on palladium/copper electrodes has been studied using differential electrochemical mass spectroscopy (DEMS), rotating ring-disk electrodes (RRDE) and quartz microbalance electrodes (ECQM). In acidic electrolytes, the activity increases linearly with Cu coverage, in alkaline electrolytes, a different dependence on coverage is observed. One monolayer of Cu gives a different selectivity from bulk copper. The adsorption of NO3- is competitive with SO42-, whereas Cl- adsorption blocks the reduction. Competitive adsorption lowers both the activity and the selectivity to N-2. Copper activates the first electron transfer, the role of palladium is to steer the selectivity towards N-2. The trends in activity and selectivity are explained in terms of coverage of N-species. (C) 2000 Elsevier Science B.V. All rights reserve

The role of adsorbates in the electrochemical oxidation of ammonia on noble and transition metal electrodes

The activity for ammonia oxidation and the intermediates formed during the reaction have been studied on platinum, palladium, rhodium, ruthenium, iridium, copper, silver and gold electrodes. The activity in the selective oxidation to N-2 is related directly to the nature of the species at the surface: the electrode is active if NHads (or NH2,ads) is present and deactivates when N-ads is present. The potential at which NHads or N-ads is formed is metal dependent. The observed trend in the strength of adsorption of N-ads is Ru > Ph > Pd > Ir > Pt much greater than Au, Ag, Cu. This trend corresponds well with the trend observed in the calculated heat of adsorption of atomic nitrogen, with iridium being an exception. Platinum is the best catalyst for this reaction because N-ads is formed at high potential, compared to rhodium and palladium, but seems to stabilize NHads rather well. Gold, silver and copper do not form NHads or N-ads, and show only an activity when the surface becomes oxidized. The metal electrodissolution is enhanced by ammonia under these conditions. Most metals produce oxygen- containing products, like NO and N2O, at potentials where the surface becomes oxidized. (C) 2001 Elsevier Science B.V. All rights reserve