Turning on the Photoelectrochemical Responses of Cd Probe-Deposited g-C₃N₄ Nanosheets by Nitrogen Plasma Treatment toward a Selective Sensor for H₂S

Abstract

A selective photoelectrochemical (PEC) sensor has been designed for the signal-on detection of H2S using g-C3N4 nanosheets that were treated with N2 plasma for depositing Cd probes. It was discovered that the yielded Cd/N@g-C3N4 nanocomposites could present enhanced photocurrents of specific responses to H2S under visible light irradiation, in contrast to the ones without the pretreatment of N2 plasma showing no H2S response. Herein, the Cd probes deposited on g-C3N4 nanosheets might react with H2S to generate CdS on Cd/N@g-C3N4, forming the efficient heterojunctions. Especially, the plasma-derived N contents might act as the “bridge” to promote charge transfer between the generated CdS and g-C3N4, resulting in the “signal-on” PEC responses to H2S. A selective PEC sensor was thereby developed for sensing H2S of concentrations linearly ranging from 40.0 to 10,000 pM, with a detection limit of about 21 pM. Also, the feasibility of sensing H2S in industrial waste gas was demonstrated by recovery tests. More importantly, this N2 plasma treatment route for g-C3N4 nanosheets may open a new door toward the construction of a Cd probe-based heterojunction for the signal-on PEC sensing platform, which is promising for the wide application in the fields of environmental monitoring, food safety, and biomedical analysis.

Ultrasensitive photoelectrochemical platform with micro-emulsion-based p-type hollow silver iodide enabled by low solubility product (K sp) for H2S sensing

“…To acquire good H 2 S sensing performance of hollow AgIbased PEC platform, the optimal conditions including pH, accumulation time, and the modification amount of hollow AgI were investigated with the help of 10 nM H 2 S (Figure 3). As seen in Figure 3a, the as-developed PEC sensor platform could present highly stable PEC responses to H 2 S in either the acidic or alkaline conditions, which is consistent with the reported work [12] . Figure 3b shows the decreases of photocurrent response regularly with the extending of incubation time, and there is no obvious change of the photocurrent signals after 20 min, in which min is chosen as the optimal incubation time.…”

“…Freshly prepared Na 2 S solutions were used as H 2 S donor. Then, the modified GCE was immersed in the Na 2 S aqueous solution with the concentration of 0, 0.1 fM, 1 fM, 10 fM, 100 fM, 1 pM, 10 pM, 100 pM, 1 nM, 10 nM for 20 min, followed by washed with ultrapure water to remove unreacted ions [12] . The PEC measurement of the modified photoelectrode was executed in phosphate buffer (0.1 M, 10 mL, pH=7.0) under a visible-light irradiation at an applied potential of 0 V.…”

“…Compared with the conventional electrochemical detection, the low background noise endows PEC sensing a highly sensitivity while it relies on the signal increment or decrement of photocurrent response [10,11] . Although PEC sensing has those advantages, H 2 S has high affinity to react with most of the photosensitizers that may affect the signal output of PEC sensing platform [10,12] . To address this issue, much effort still needs to be devoted to seek applicative photoelectrode materials for the high accuracy and sensitivity for H 2 S quantitative analysis.…”

Au NP-Decorated g-C3N4-Based Photoelectochemical Biosensor for Sensitive Mercury Ions Analysis

“…In order to improve the photoelectric performance of g-C 3 N 4 , many researchers have focused on modifying g-C 3 N 4 to boost the charge separation through element doping, sensitization, and semiconductor coupling. 39 , 40 In particular, a semiconductor modified with metal nanoparticles (NPs) could effectively improve the photoelectric performance of the semiconductor for two reasons. One is that metal nanoparticles, a type of conductive material with a large specific surface area and unique photoelectric performance, could promote electron capture and transfer in the semiconductor.…”

Near‐infrared Responsive Photoelectrochemical Biosensors

“…Nevertheless, in most cases, the photosensitive working electrodes were comprised of multicomponent nanocomposites, which was in order to improve the photo‐to‐electric conversion efficiencies and the separation and transfer of photogenerated electrons/holes, like core‐shell QDs and heterojunctions [25–26]. Particular attention also has been paid to the specific morphologies of the photosensitive material, e. g., 1‐D nanotubes [27] and nanowires [28], 2D nanosheets [29], 3D array architectures [30], which has a profound impact on the analytical performances of PEC sensors as well. Up to now, though, plenty of efforts have been devoted to investigating the photosensitive materials, most current PEC sensors were excited by ultraviolet‐visible (UV‐vis) light, which hampers their future applications in bioanalysis, e. g. in vivo detection, due to the intrinsic limitation of short penetration of UV/vis light.…”