Development of cost-effective, efficient, and durable electrocatalysts for oxygen evolution reaction (OER) with fast kinetic reaction is highly significant, considering the elevated thermodynamic energy barrier involved in water electrolysis. To overcome such challenges, an innovative vapor phased iron-doping strategy is employed on carbon nanotubes (CNT)-interlinked metal-organic framework (MOF) nanosheets (Ni-MOF@CNT) to obtain mixed metal oxide and metal heteronanoparticles superficially implanted partially (semi)-decomposed MOF nanosheets (Ni-M@C-400). These semi-MOF nanosheets attain the structural privileges related to MOF-nanostructure, mixed metal nanoparticles synergism, interconnected-CNT assisted high conductivity, and mechanical strength. As a result, Ni-M@C-400 exhibits exceptional OER activity with overpotential as low as 229 mV to reach the benchmark current density of 10 mA/cm² (η₁₀) and exhibits greatly reduced thermodynamic barrier (Tafel slopes of 40.51 mV/dec) along with significant durability for ~ 60 h. More importantly, this sublimated iron-doped semi-MOF (Ni-M@C-400) displays significantly better OER performance over the corresponding annealed bimetallic MOF (NiFe-M@C-400: 270 mV at η₁₀). Moreover, the successful incorporation of vapor phased iron into variety of MOFs (Cr, Mn, Co, Ni, and Cu) approved its uniqueness and the universality. This work provides an innovative vapor phased heteroatom-doping strategy to develop cost-effective and efficient electrocatalysts for water electrolysis.

Designing and fabricating the bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has long posed an uphill and pressing task for the interconversion of electricity and chemicals. Baring this in mind, herein, we propose a novel hierarchical nanoarchitecture of N-doped carbon nanotubes capped with carbon layer armored CoFe alloy (CoFe@NC-NT), which is facilely fabricated by spray drying and subsequent annealing process. As a bifunctional electrocatalyst, the well-designed CoFe@NC-NT shows a remarkably low overpotential of 257 mV and a half-wave potential of 0.74 V to obtain 10 mA·cm⁻² in OER and ORR, respectively. Meanwhile, it is also characterized by exceptional operating stability to meet practical application for Zn-air batteries. The high catalytic activity of CoFe@NC-NT is attributed to the tight contact between the highly conductive nanotubes and metal alloy nanoparticles. And the qualified stability is ascribed to the coating effect of carbon layer shell to alloy core. Given the unique structural evolution with enhanced oxygen-involved reaction activity, we believe that this work can provide an appealing innovative approach towards the directed self-assembly of functional nanostructures to realize satisfying overall performance.