Scheme 1. Wavelength-dependent ROS regulation on T4EPE-Cu. Different from previous work focusing on the generation of a single ROS at a specific site accordingly, O₂ adsorbed at Cu-alkynyl site can be regulated into different ROS under different photo-excitation wavelengths with a regulation range of 1.3~10.7 (¹O₂ : O₂∙-).

Figure 1. Morphology and structure of T₄EPE and T₄EPE-Cu. (a) TEM images of T₄EPE-Cu. (b) STEM images of T₄EPE-Cu. (c) Powder XRD patterns of the prepared samples and simulation of T₄EPE-Cu by Materials studio software. (Inset: the structure diagram of {Cu-Cu} subunit). (d) The schematic structures of T₄EPE-Cu. (e) High-resolution XPS of C 1s spectra in T₄EPE and T₄EPE-Cu. (f) Nitrogen adsorption-desorption isotherms of the prepared samples. In the ball-and-stick model of T₄EPE-Cu, the gray, green and orange spheres represent C, H and Cu respectively.

Figure 2. Charge separation performance on T₄EPE and T₄EPE-Cu. (a) Diffuse reflectance absorption spectra (inset: the optical photos of the prepared samples). (b) Band structure treated by Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional against Fermi level and PDOS of T₄EPE-Cu. (inset: optimised geometric structures of T₄EPE-Cu, the colour of ball-and-stick model refers to Figure 1). (c) Charge distribution pattern. (d) Transient photocurrent of different single band. (e) Solid fluorescence intensity spectra. Photoexcited wave-length is 380 nm.

Figure 3. Experiment with theoretical calculations reveal photo-regulated ROS selective generation mechanism on T₄EPE-Cu. (a) The products schematic diagram of photocatalytic oxidation a-terpinene. Reaction conditions: substrate (0.1 mmol), T₄EPE-Cu catalyst (10 mg), CH₃CN (5 mL), air. (b) Control experiments of photocatalytic oxidation a-terpinene. (c) Free radical capture experiments on α-terpinene oxidation. Na₂S₂O₈, methanol, carotene, superoxide dismutase (SOD) and mannitol were added respectively as e-, h+, ¹O₂, O₂∙- and ∙OH scavengers. Reaction conditions: a-terpinene (0.1 mmol), scavenger (0.1 mmol), catalyst (10 mg), CH₃CN (5 mL), air, 420 nm, 2 h. (d) Conversion rate of a-terpinene oxidation under different photoexcitation wavelengths. TPV curves (inset: tmax and charge integral area represent the time and amount of charge extraction, respectively) under 355 nm light excitation (e) and 532 nm light excitation (f). (g) Calculated charge density difference in the presence and absence of an electron with the isosurfaces value of 0.012 e/ų (yellow represents charge accumulation). (h) The optimized oxygen adsorption model at Cu-alkynyl moiety (Model 3). The O-PDOS treated by Perdew-Burke-Ernzerhof (PBE) functional before (i) and after (j) adding an electron in Model 3. The positive and negative y values represent majority and minority spin states, respectively. The vertical dashed line shows Fermi level.