Au/Cdot-Nanohybrid Electrocatalyst Synthesized by Rice-Straw-Derived Carbon Dots as a Reducing Agent for Improved Hydrogen Evolution Reactions

Abstract

We report a facile method by which to synthesize Au/Cdot nanohybrids using carbon dots (Cdots) obtained from rice straw as a direct reducing agent as well as a stabilizer. Rice-straw-derived Cdots possess oxygen-containing functional groups that act as an electron-donating source to reduce Au3+ to Au0 without the use of chemical reagents for the reduction of Au precursors. Additionally, the strong Au-carbon interaction promotes a high electron transfer of the Au/Cdot nanohybrid electrocatalyst, resulting in enhanced performance of the hydrogen evolution reaction (HER). The overpotential is 150 mV at a current density of 10 mA·cm−2 and the TOF value is 0.06·s−1, representing the most outstanding HER performance among Au-based catalysts as a non-Pt HER electrocatalyst. The HER activity is stably maintained for 2000 cycles as well as for 48 h. The synthesis of Cdots, the hybridization of Au/Cdot electrocatalyst, and the production of clean hydrogen fuel using Au/Cdots are zero CO2 emission strategies, not only preventing the emission of pollutants but also satisfying the energy needs of humankind.

Preparation of carbon dots-metal nanoparticles nanocomposites and their application in heterogeneous catalysis

“…Therefore, the as-prepared CQDs/Ag and CQDs/Au nanocomposites have smaller particle sizes of 11 ± 6 and 15 ± 6 nm, respectively. The particle size was smaller than that of the same nanocomposites prepared with other methods, such as CQDs/Au by impregnation (20-50 nm) [62] and CQDs/Ag by impregnation (20-30 nm) [88]. However, the application of electron beam irradiation in the preparation of CDs-MNPs nanocomposites is still rare.…”

“…In the impregnation process, magnetic stirring is mostly used. Nguyen et al at first prepared into CQDs from rice straw by hydrothermal method [62]. Then they added HAuCl 4 solution to the CQDs suspension dropwise and made them fully react by magnetic stirring.…”

“…A few literatures briefly mentioned purification methods. Most of them only performed simple centrifugation separation on the nanocomposites [62,63,66,76,83,[95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111]. Through comparison, it was found that the supernatant of CDs was collected as the product during the preparation of CDs, while the precipitate of the nanocomposites was centrifuged as the product during the preparation of nanocomposites.…”

Current trends in carbon-based quantum dots development from solid wastes and their applications

“…CQDs are synthesized from a variety of biodegradable sources, such as manure (D’Angelis do E. S. Barbosa et al 2015 ; Horst et al 2021 ), hair (Guo et al 2016 ; Liu et al 2014 ; Singh et al 2020 ), plant roots (D’souza et al 2018 ; Yu et al 2019 ), stems (Vandarkuzhali et al 2017 ), fruit and vegetable peels and shells (Ang et al 2020 ; Atchudan et al 2021 ; Bankoti et al 2017 ; Cheng et al 2017 ; Hu et al 2021 ; Prasannan and Imae 2013 ; Qureshi et al 2021 ; Rajamanikandan et al 2021 ; Surendran et al 2020 ; Tyagi et al 2016 ; Vandarkuzhali et al 2018 ; Wang et al 2020 ; Xue et al 2016 ; Yang et al 2021 ), tea waste (Chen et al 2019 ; Zhu et al 2019 ), wheat straw (S. Liu et al 2021a , b ; Yuan et al 2015 ), animal shell (Gedda et al 2016 ; Yao et al 2017 ), expired milk (Athika et al 2019 ; Su et al 2018 ), feathers (Liu et al 2015 ; Ye et al 2017 ), egg shell (Pramanik et al 2018 ; Wang et al 2012 ; Ye et al 2020 ), whey (Devi et al 2017 ), waste paper (Devi et al 2018 ; Jeong et al 2018 ; Park et al 2020 ), cat feedstocks (Ahn et al 2019 ), soot (Thulasi et al 2020 ; Tripathi et al 2014 ; Venkatesan et al 2019 ), waste oil (Y. Hu et al 2014a , b ; Mahat and Shamsudin 2020 ), petroleum coke (Wang et al 2015a ), sugarcane waste (Pandiyan et al 2020 ; Xu-Cheng et al 2018 ), rice waste (Anthony et al 2020 ; Nguyen et al 2021 ), and wa...…”

A Novel Trimetal Phosphide with Amorphous Porous Structure for the Enhanced Electrocatalysis of Oxygen Evolution Reaction

“…Electrocatalytic water splitting has always been favored by researchers due to its economic and environmentally friendly characteristics. [1][2][3] However, the sluggish kinetic process leads to high overpotential and low efficiency in its practical applications. 4,5 At present, noble metal-based electrocatalysts are considered to be very effective catalysts for OER, such as iridium and rutheniumbased composite materials.…”