Electric field–confined synthesis of single atomic TiO <i> _x </i> C <i> _y </i> electrocatalytic membranes

Electrocatalysis exhibits certain benefits for water purification, but the low performance of electrodes severely hampers its utility. Here, we report a general strategy for fabricating high-performance three-dimensional (3D) porous electrodes with ultrahigh electrochemical active surface area and single-atom catalysts from earth-abundant elements. We demonstrate a binder-free dual electrospinning-electrospraying (DESP) strategy to densely distribute single atomic Ti and titanium oxycarbide (TiO<i>_x</i>C<i>_y</i>) sub-3-nm clusters throughout interconnected carbon nanofibers (CNs). The composite offers ultrahigh conductivity and mechanical robustness (ultrasonication resistant). The resulting TiO<i>_x</i>C<i>_y</i> filtration membrane exhibits record-high water purification capability with excellent permeability (~8370 liter m^-2 hour^-1 bar^-1), energy efficiency (e.g., >99% removal of toxins within 1.25 s at 0.022 kWh·m^-3 per order), and erosion resistance. The hierarchical design of the TiO<i>_x</i>C<i>_y</i> membrane facilitates rapid and energy-efficient electrocatalysis through both direct electron transfer and indirect reactive oxygen species (¹O₂, <b>·</b>OH, and O₂<b>·</b>^-, etc.) oxidations. The electric field-confined DESP strategy provides a general platform for making high-performance 3D electrodes.