Oxidized Detonation Nanodiamonds Act as an Efficient Metal‐Free Photocatalyst to Produce Hydrogen Under Solar Irradiation

Abstract

Herein, it is revealed for the first time that oxidized detonation nanodiamonds (Ox‐DND) can produce hydrogen under solar irradiation without addition of cocatalyst or formation of heterojunction with another semiconductor. This hydrogen production is investigated using two sacrificial reagents and compared to the one of hydrogenated detonation nanodiamonds (H‐DND). The effect of the Ox‐DND and sacrificial reagent concentrations on the hydrogen production is also studied. At its maximum, a H2 production yield of 32 μmol h−1 is obtained for a Ox‐DND concentration of 12.5 μg mL−1 (using only 1 vol% of triethanolamine as sacrificial reagent), similar to the one of TiO2 nanoparticles tested at the same concentration in the same illumination conditions.

Utilizing Constant Energy Difference between sp-Peak and C 1s Core Level in Photoelectron Spectra for Unambiguous Identification and Quantification of Diamond Phase in Nanodiamonds

“…We should emphasize, however, that the measured position of peaks could be affected by surface band bending [11], but the relative energy difference between C 1s and sp-peak should not. The measured energy differences between the C 1s peak components and the sp-peak positions were 271.3 ± 0.1 eV (for sp 3 ) and 270.7 ± 0.1 eV (for sp 2 ). These relative binding energy differences were used for identification of the sp 3 and sp 2 components in the C 1s spectra from ND samples.…”

“…HPHT NDs are generally larger than DND NDs, with particles exhibiting uniform monocrystalline and highly irregular shapes. HPHT NDs also demonstrate reduced and surface-limited non-diamond sp 2 carbon phase content relative to DNDs [9].…”

“…Their crystalline diamond core imparts structural stability and biocompatibility, while the ability to tailor surface chemistry and functional groups allows controllable interaction with various systems. As a catalytically active material, NDs show promise for photo-and electrocatalytic reactions like nitrogen reduction [1] or hydrogen production [2]. They may also find use in energy storage as electrode materials in batteries and supercapacitors [3].…”