Plasmon-Enhanced Solar-Driven Hydrogen Evolution Using Titanium Nitride Metasurface Broadband Absorbers

Abstract

Broadband perfect absorbers in the visible region have attracted considerable attention in many fields, especially in solar thermophotovoltaic and energy harvesting systems. However, developing light absorbers with high absorptivity, thermal stability, and a broad bandwidth remains a great challenge. Here, we theoretically and experimentally demonstrate that a titanium nitride metasurface absorber exhibits broadband absorption with an average absorption of more than 92% over a wavelength range of 400 to 750 nm. The increase in absorption is attributed to the localized surface plasmon resonance (LSPR). We demonstrate the plasmon-enhanced visible-light-driven hydrogen production from water using a polymer photocatalyst integrated with a TiN metasurface absorber. A 300% increase in the hydrogen evolution rate was observed due to the LSPR that enhances the rates of light absorption, carrier separation, and hot-carrier transfer in polymer photocatalyst. These results enable a new approach to prepare high-efficiency solar energy harvesting systems.

Solvent polarity tuning to enhance the crystallinity of 2D-covalent organic frameworks for visible-light-driven hydrogen generation

“…S10 †). Furthermore, their 13 C-NMR spectra showed a signal at 158.1 and 159.6 ppm for the BT-Py Solvent and BT-Cz Solvent COFs, respectively (Fig. 2a and b), conrming again the formation of an imine bond.…”

“…1e shows the lattice fringes, which suggests an orderly alignment with a high degree of crystallinity. Fourier transform infrared (FT-IR) spectroscopy, solid-state 13 C-nuclear magnetic resonance ( 13 C-NMR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used to assess the chemical structure of these COFs. The FT-IR spectra reveal a stretching vibration band at around 1625 cm À1 assigned to the C]N bond, indicating the formation of an imine linkage (Fig.…”

“…2a and b), conrming again the formation of an imine bond. A full assignment of all resonances for other 13 C-NMR spectra of COFs is shown in Fig. 2a and b.…”

“…The theoretical and experimental 13 C NMR results of the BT-Py Solvent and BT-Cz Solvent COFs are shown in Fig. 2a and b.…”

“…4,5 Recently, 2D COFs have been revealed as a potential type of excellent photocatalyst for H 2 generation under visible light due to their unique properties, such as prominent visible light absorbance, large surface areas, tunable bandgaps, and long-range ordered structures beside pp stacked architectures, which can improve their charge-carrier mobilities, charge separation, and optical properties. [6][7][8][9] A number of conjugated organic photocatalysts, including linear polymers, [10][11][12][13] polymer dots, 14,15 hydrophilic polymers, and conjugated microporous polymers (CMPs), [16][17][18][19][20][21] have been used for photocatalytic hydrogen generation from water under visible light. However, COF materials are distinguished from polymer photocatalysts by (a) an ideally one-step reaction, (b) limited solvent wastage, (c) high reaction yields, (d) a cheap and available co-catalyst, (e) high crystallinity, and (f) efficient charge transfer.…”