Two-dimensional (2D) MXene materials are promising candidates for the development of heterogeneous materials, yet deciphering structural impacts on their inherent physical properties poses significant challenges. We introduce structurally regulated 2D Ti₃C₂ nanosheets that were fabricated using high intensity focused ultrasound (HIFU) method. These nanosheets were easily produced in large quantities with a high yield of 94.4% and exhibited excellent photothermal and electrochemical catalytic properties. By utilizing this monolayer H-Ti₃C₂ (HIFU-treated Ti₃C₂), the heterogeneous integration exhibited promising performance in subsequent applications. By integrating with a hydrogel matrix (H-Ti₃C₂, 0.1 wt.%), it demonstrated a photothermal conversion efficiency reaching 43.08%, and the maximum temperature increased by 48.14% under near-infrared (NIR) irradiation. Additionally, these 2D nanosheets were also utilized in fabricating electrochemical sensors to evaluate electrochemical-catalytic capabilities. Notably, it confirmed that the electrocatalytic activity of heterogeneous Au/H-Ti₃C₂ in electrochemical dopamine (DA) detection, and it proved the exhibition of sensitivity (0.012 μA/μM), low detection limit (0.15 μM), and excellent anti-interference performance and stability. The enhanced activity was ascribed to synergistic effect of Au and the increased number of accessible active sites on the nanosheets. This work not only sheds light on the structure–property relationship of 2D Ti₃C₂ but also broadens the application scope of typical dimensional materials for controlling and producing in biological and sensing applications.

Hydrogen is garnering growing attention as a green energy source with zero carbon emissions. However, most hydrogen production technologies still rely on the consumption of fossil fuels and are therefore unsustainable. This has driven the search for more environmentally friendly methods of hydrogen production. In this work, we present an innovative approach to enhance hydrogen generation via electrostatic interaction in the Escherichia coli and defective titanium dioxide (TiO_2−x) biohybrids. Our method involves narrowing the forbidden bandwidth of TiO₂ while introducing defect bands into its conduction band to facilitate visible light absorption and efficient charge separation. This biohybrid system, consisting of E. coli and TiO_2−x, demonstrates a remarkable capability to produce 1.25 mmol of hydrogen within a 3-h timeframe under visible light irradiation. This accomplishment signifies a 3.31-fold rise in hydrogen production in comparison to E. coli, signifying a substantial enhancement in hydrogen production efficiency. Furthermore, we delve into the alterations in biological metabolites associated with hydrogen production and the changes in electron transfer in different biohybrid systems. It provides valuable insights into the understanding of the intrinsic mechanisms that drive the process. This work introduces a novel and promising avenue for achieving this exciting goal.