Colloidal carbon quantum dots as light absorber for efficient and stable ecofriendly photoelectrochemical hydrogen generation. (August 2021)

• Record Type: Journal Article
• Authors: Wang, Xiaohan; Wang, Maorong; Liu, Guiju; Zhang, Yuanming; Han, Guangting; Vomiero, Alberto; Zhao, Haiguang
• Is Part Of: Nano energy. Volume 86(2021)
• Publication Date: 2021-08
• Subjects: Carbon quantum dots -- Photoelectrochemical cells -- Glucose -- Hydrogen evolution -- Water splitting; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.106122
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Solar-driven hydrogen production is one of the most promising strategies for solar-to-hydrogen energy conversion. Compared to inorganic quantum dots (QDs), carbon quantum dots (C-dots) have attracted a lot of attention for optoelectronic devices due to their structure-dependent optical properties and green composition. However, the solar-to-hydrogen conversion efficiency of most of the photoelectrochemical (PEC) devices based on colloidal QDs is still low. Here we demonstrated a highly efficient and stable ecofriendly PEC device using C-dots sensitized TiO2 photoanode, Pt loaded on carbon nanofibers as counter electrode, and glucose aqueous solution as electrolyte. The red-color C-dots were prepared using a solvothermal reaction, with an absorption spectrum ranging from 300 to 600 nm and a quantum yield (QY) of 50%. The C-dots have excitation independent photoluminescence peak positions and highly crystalline structure. The hydroxyl group on the C-dots can strongly interact with the TiO2, forming a very stable complex. Benefiting from these features, the PEC devices based on C-dots exhibit a saturated photocurrent density as high as ~4 mA/cm 2 at 0.6 V vs. RHE and the device is very stable (keeping 95% of its initial value after 10-hour illumination upon 100 mW/cm 2 ). This work indicates the promising properties of the C-dots/TiO2 system, which holds huge potential for applications in the fields of optoelectronic and catalytic devices. Graphical Abstract: ga1 Highlights: The red C-dots have an excitation independent emission peak and highly crystalline structure with dominant energy levels. A PEC device consists of C-dots/TiO2 as photoanode, Pt/CNFs as CE, and glucose aqueous solution as electrolyte. The PEC device exhibits saturated photocurrent density as high as ~ 4 mA/cm 2 at 0.6 V vs. RHE and the device is very stable.