The facile reconfiguration of phases plays a pivotal role in enhancing the electrocatalytic production of H₂ through heterostructure formation. While chemical methods have been explored extensively for this purpose, plasma-based techniques offer a promising avenue for achieving heterostructured nano-frameworks. However, the conventional plasma approach introduces complexities, leading to a multi-step fabrication process and challenges in precisely controlling partial surface structure modulation due to the intricate interaction environment. In our pursuit of heterostructures with optimized oxygen evolution reaction (OER) behavior, we have designed a facile auxiliary insulator-confined plasma system to directly attain a Ni₃N-NiO heterostructure (hNiNO). By meticulously controlling the surface heating process during plasma processing, such approach allows for the streamlined fabrication of hNiNO nano-frameworks. The resulting nano-framework exhibits outstanding catalytic performance, as evidenced by its overpotential of 320 mV at current densities of 10 mA cm^-2, in an alkaline environment. This stands in stark contrast to the performance of sNiNO fabricated using the conventional plasma method. Operando plasma diagnostics, coupled with numerical simulations, further substantiate the influence of surface heating due to auxiliary insulator-confinement of the substrate on typical plasma parameters and the formation of the Ni₃N-NiO nanostructure, highlighting the pivotal role of controlled surface temperature in creating a high-performance heterostructured electrocatalyst.

Photocatalytic hydrogen generation represents a promising strategy for the establishment of a sustainable and environmentally friendly energy reservoir. However, the current solar-to-hydrogen conversion efficiency is not yet sufficient for practical hydrogen production, highlighting the need for further research and development. Here, we report the synthesis of a Sn-doped TiO₂ continuous homojunction hollow sphere, achieved through controlled calcination time. The incorporation of a gradient doping profile has been demonstrated to generate a gradient in the band edge energy, facilitating carrier orientation migration. Furthermore, the hollow sphere’s outer and inner sides provide spatially separated reaction sites allowing for the separate acceptance of holes and electrons, which enables the rapid utilization of carriers after separation. As a result, the hollow sphere TiO₂ with gradient Sn doping exhibits a significantly increased hydrogen production rate of 20.1 mmol·g⁻¹·h⁻¹. This study offers a compelling and effective approach to the designing and fabricating highly efficient nanostructured photocatalysts for solar energy conversion applications.