Thermocatalysts Through the Lens of Nanoscale Semiconductor Heterojunctions: Plasma‐Deposited CoO/WO 3 Nanohybrid Films

Abstract Hybrid nanomaterials composed of semiconducting nanoparticles offer exciting opportunities in thermocatalysis, yet the underlying mechanisms governing their interactions remain elusive. Commonly attributed to vague notions of “synergy” or “anti‐synergy,” these effects lack a clear physical basis. Herein, plasma‐deposited CoO/WO 3 thin‐film nanohybrids are reported and their behavior in CO 2 hydrogenation is investigated. Using XPS, XRD, and HRTEM, the formation of nano‐heterojunctions with charge regions on the scale of individual nanoparticles is uncovered. This finding provides a conceptual framework for understanding synergistic effects in thermocatalytic systems, revealing how nanoscale charge modulation, controlled by the design of appropriate heterojunctions, governs catalytic activity and offers a new lens through which to interpret complex nanoparticle interactions in hybrid materials.