Polyaniline/Carbon Dots Composite as a Highly Efficient Metal-Free Dual-Functional Photoassisted Electrocatalyst for Overall Water Splitting

Abstract

Photoassisted electrocatalytic (P-EC) water splitting for H2 production has received much attention. Here, we report a metal-free bifunctional photoassisted catalyst of a polyaniline/carbon dots (PANI/CDs) composite for overall water splitting. In a neutral electrolyte, under visible light, the overpotentials of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) for PANI/CDs/NF are reduced by 150 and 65 mV to reach the current densities of 30 and 20 mA cm–2, respectively. In a full water-splitting cell, under visible light, the current density is 13.27 mA cm–2 at 2.0 V, which increases by 62.8% compared with that under the dark conditions (8.15 mA cm–2). The in situ transient photovoltage (TPV) tests were used to study the light-induced effects on half-reactions of water splitting, as well as the charge-transfer kinetic characteristics at the catalyst interface.

Replacing Ru complex with carbon dots over MOF-derived Co3O4/In2O3 catalyst for efficient solar-driven CO2 reduction

“…Carbon dots (CDs), with a size less than 10 nm, have attracted wide attention for photocatalytic activity, due to their facile preparation, high stability and low cost. 21–25 As a fascinating photosensitizer, CDs exhibit good electron transfer/reservoir properties, which can inhibit the recombination of photoexcited electron–hole pairs, and CDs with conjugated π structures can preferentially adsorb and activate CO 2 , which is the primary step for solar-driven CO 2 conversion. 26 In addition, due to their abundant surface functional groups, CDs can be easily anchored onto metal oxide nanostructures, and promote interfacial contact, boost charge separation and stabilize the generated electrons or holes.…”

Organic Semiconductor/Carbon Dot Composites for Highly Efficient Hydrogen and Hydrogen Peroxide Coproduction from Water Photosplitting

“…For DAnTMS, the peak at around 1637 cm –1 is attributed to the stretching vibration of CC, and the small peak at around 2376 cm –1 is due to the stretching vibration of CC. Similarly for CDs, the peaks at 3445, 1726, and 1230 cm –1 can be attributed to the vibration of O–H, CO, and C–O–C, respectively. , Finally, for DAnTMS/CDs, all the typical peaks of DAnTMS and CDs can be observed. Therefore, taking the results of TEM, XPS, Raman, and FT-IR into account, CDs have successfully adsorbed on DAnTMS.…”

“…Similarly for CDs, the peaks at 3445, 1726, and 1230 cm −1 can be attributed to the vibration of O−H, C O, and C−O−C, respectively. 47,48 Finally, for DAnTMS/CDs, all the typical peaks of DAnTMS and CDs can be observed. Therefore, taking the results of TEM, XPS, Raman, and FT-IR into account, CDs have successfully adsorbed on DAnTMS.…”

“…Figure e,f shows that under different conditions, Δ Q , which is defined as the number of charges consumed in the reactions, ,, was calculated by integrating the TPV curves. Under MeCN with 0.5 vol % H 2 O atmosphere, Δ Q of DAnTMS/CDs (Δ Q 4 = 0.0654) becomes lower than that of DAnTMS (Δ Q 3 = 0.1495), indicating that CDs promoted the H + reduction, which consumed electrons and hindered H 2 O oxidation, which would produce electrons.…”

“…37,38,45 Figure 1e shows the Raman spectra of DAnTMS, CDs, and DAnTMS/CDs, where for DAnTMS, there is a typical peak at about 1300 cm −1 , while for CDs, there are two distinct peaks located at 1330 and 1600 cm −1 , which can be attributed to the D band of the sp 3 -banded carbon atoms in disordered graphite and the G band from in-plane vibration of sp 2 carbon, respectively. 46,47 DAnTMS/CDs combine the characteristic peaks of DAnTMS and CDs. Fourier transform infrared spectroscopy (FT-IR) was utilized to explore the surface functional groups of DAnTMS, CDs, and DAnTMS/CDs, as shown in Figure 1f.…”