The alkaline hydrogen oxidation reaction (HOR) involves
the coupling
of adsorbed hydrogen (Had) and hydroxyl (OHad) species and is thus orders of magnitude slower than that in acid
media. According to the Sabatier principle, developing electrocatalysts
with appropriate binding energy for both intermediates is vital to
accelerating the HOR though it is still challenging. Herein, we propose
an unconventional bilateral compressive strained Ni–Ir interface
(Ni–Ir(BCS)) as efficient synergistic HOR
sites. Density functional theory (DFT) simulations reveal that the
bilateral compressive strain effect leads to the appropriate adsorption
for both Had and OHad, enabling their coupling
thermodynamically spontaneous and kinetically preferential. Such Ni–Ir(BCS) is experimentally achieved by embedding sub-nanometer
Ir clusters in graphene-loaded high-density Ni nanocrystals (Ni–Ir(BCS)/G). As predicted, it exhibits a HOR mass activity of
7.95 and 2.88 times those of commercial Ir/C and Pt/C together with
much enhanced CO tolerance, respectively, ranking among the most active
state-of-the-art HOR catalysts. These results provide new insights
into the rational design of advanced electrocatalysts involving coordinated
adsorption and activation of multiple reactants.
In recent years, heavy metals and organic pollutants have become two major obstacles to maintaining the ecological environment. Thus, choosing efficient and environmentally friendly methods and materials to remediate heavy metals and organic pollution has become a hot research topic. Porous metal–organic frameworks (MOFs) and their composites or derivatives can be used as ideal adsorbents and catalytic materials because of their unique structures and functions. This work reviews the research progress on MOF-based materials in the remediation of the water environment in the past decade. The MOF-based materials discussed here mainly include MOF composites obtained by fabrication and MOF derivatives obtained by pyrolysis. Both MOF composites and MOF derivatives are optimized materials that exhibit adsorption or catalytic performance superior to the pristine MOFs. Additionally, the interactions and mechanisms between the MOF-based materials and different heavy metals or organic pollutants are discussed in detail. Finally, some problems or defects of the MOF-based materials are also proposed considering the materials’ economic efficiency, stability and safety. There is still a long way forward for the real application of MOF-based materials. Further efforts are also needed to explore and expand the environmental remediation scope of MOF-based materials.
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