Novel g‑C₃N₄/C/Fe₂O₃ Composite for Efficient Photocatalytic Reduction of Aqueous Cr(VI) under Light Irradiation

Research on the rational design of photocatalysts for efficient hexavalent chromium (Cr­(VI)) reduction from Cr­(VI)-containing wastewater has attracted widespread attention. In this paper, a novel g-C3N4/C/Fe2O3 photocatalyst was successfully synthesized by anchoring g-C3N4 nanosheets onto C/Fe2O3 that was prepared using collagen fiber as the biochar resource following the Fe tanning mechanism to reduce Cr­(VI) under artificial solar irradiation. Under the same conditions, the as-prepared g-C3N4/C/Fe2O3 photocatalyst exhibited higher Cr­(VI) reduction efficiency than g-C3N4, and the Cr­(VI) reduction efficiency increased as Fe content in the g-C3N4/C/Fe2O3 photocatalyst increased. The enhanced photocatalytic performance was primarily ascribed to the formation of an indirect Z-scheme heterojunction between C/Fe2O3 and g-C3N4, which improved the separation efficiency of the photogenerated charge carrier. Furthermore, radical trapping indicated that photoinduced electrons (e–) were the main factor for Cr­(VI) reduction. This work provides guidance for high value-added utilization of collagen fiber in constructing efficient light-driven photocatalysts and practical Cr­(VI) removal from wastewater

Additional file 1: of Facile Synthesis of Nitrogen-Doped Microporous Carbon Spheres for High Performance Symmetric Supercapacitors

Figure S1. The assemble process of NMCSs-600-based symmetric supercapacitors. Figure S2. The high-resolution C 1 s spectra of the as-prepared NMCSs materials at different carbonization temperatures of (a) 500 °C, (b) 600 °C, (c) 700 °C and (d) 800 °C. Figure S3. The high-resolution O 1 s spectra of the as-prepared NMCSs materials at different carbonization temperatures of (a) 500 °C, (b) 600 °C, (c) 700 °C and (d) 800 °C. Figure S4. The cycling performance of the NMCSs-600-based SSD at current density of 10 A g− 1 for 2000 cycles. Table S1. The different resistance values of the NMCSs samples. Table S2. Comparison of energy density and power density data reported for different CSs based symmetric supercapacitor devices. (DOCX 752 kb

Influence of different factors on wear mass.

(a) Different compression loads (b) Different contact loads (c) Different friction rates (d) Different lubrication environments.</p

Experimental parameters of friction and wear under different contact loads.

Experimental parameters of friction and wear under different contact loads.</p

Effect of different experimental variables on surface morphology of Ti-6Al-4V titanium alloy plate.

(A1) is the sample photo with test group No. A1 (A2) is the sample photo with test group No. A2 (A3) is the sample photo with test group No. A3 (B1) is the sample photo with test group No. B1 (B2) is the sample photo with test group No. B2 (C1) is the sample photo with test group No. C1 (C2) is the sample photo with test group No. C2 (D1) is the sample photo with test group No. D1 (D2) is the sample photo with test group No. D2.</p

Schematic diagram of internal force on femoral stem of artificial hip joint.

F: Compression load; Fj: Contact load; f: Fiction force.</p

Internal force diagram of femoral stem of artificial hip joint.

F: Compression load Fj: Contact load f: Fiction force.</p

Experimental parameters of friction and wear under different lubrication environments.

Experimental parameters of friction and wear under different lubrication environments.</p

Friction and wear test device.

1: Friction head of bone 2: Pressure sensor 3: Ti-6Al-4V titanium alloy plate 4: Electronic testing machine 5: Sliding module 6: Linear actuator 7: Intelligent display 8: Drive motor for sliding module 9: Control box of linear actuator.</p

Relevant parameters and functions of the experimental module.

Relevant parameters and functions of the experimental module.</p