Plasmonic and Photonic Effects on Hydrogen Evolution over Chemically Modified Titania Inverse Opals

Abstract

The photonic effects of chemically modified titania inverse opals can be exploited for improving photocatalytic hydrogen production. This work reports the in situ preparation of gold-platinum nanoparticle (NP)-loaded and nitrogenfluorine co-doped titania inverse opal photocatalysts with different photonic band gaps (PBGs). In situ loading of gold and platinum NPs was carried out during the preparation of titania inverse opals by treating the titania precursor with gold chloride and platinum chloride. AuÀPt/NÀF TiO 2 IO-460 samples with the photonic effects matching the surface plasmon resonance region of Au NPs displayed a maximum activity with a hydrogen production rate of 134 mmol h À1 g À1 . The hydrogen yield (97 mmol h À1 g À1 ) obtained for AuÀPt/NÀF TiO 2 IO-215, with the photonic effects close to the electronic bandgap of titania was also high when compared to that of the nanocrystalline counterpart, AuÀPt/NÀF nc-TiO 2 (49 mmol h À1 g À1 ). Excellent solar hydrogen evolution profile was observed for in situ gold-platinum NP-loaded and nitrogen-fluorine co-doped titania inverse opal photocatalysts when compared to recent reports.[a] Dr.

Photonic Crystals for Plasmonic Photocatalysis

“…Recently, plasmonic PCs have been intensively investigated to combine both PBG and LSPR effects together in terms of physical appearances and electronic energies for various applications [104][105][106][107][108][109]. An interesting study has been shown for negative photoresist IO (prepared by SiO 2 opal embedding) deposited with gold, where the dual-colored micropatterns (Figure 3) open the door for possible applications in various fields, including cosmetics, optical filters and coatings [104].…”

“…The fabrication of PCs-based plasmonic photocatalysts is quite challenging process to load/infiltrate plasmonic NPs on/in the PCs without destroying the Bragg's diffraction property of the PCs and to retain the effective LSPR effect of NMs. The photodeposition and thermal methods have been commonly used to deposit plasmonic NPs on IO by using the adequate precursors, such as chloroplatinic acid (H 2 PtCl 6 ) for Pt [112], silver nitrate (AgNO 3 ) for Ag [113], and tetrachloroauric acid (HAuCl 4 ) for Au [106]. NMs have been deposited on TiO 2 IO either before [106] or after [99] its infiltration inside opal structure.…”

“…The photodeposition and thermal methods have been commonly used to deposit plasmonic NPs on IO by using the adequate precursors, such as chloroplatinic acid (H 2 PtCl 6 ) for Pt [112], silver nitrate (AgNO 3 ) for Ag [113], and tetrachloroauric acid (HAuCl 4 ) for Au [106]. NMs have been deposited on TiO 2 IO either before [106] or after [99] its infiltration inside opal structure. Apart from that, hydrothermal method has been proposed to load Au NPs on TiO 2 PC, enhancing the stability due to the interphase sintering between TiO 2 backbone and Au NPs [91].…”

“…In contrast, Temerov et al have discussed the enhanced mineralization of acetylene to CO2 on TiO2-IO modified with Au NPs and Ag NPs (by 53% and 39%, respectively), owning to the LSPR activation (plasmonic photocatalysis), i.e., electron transfer from NM to TiO2 with simultaneous oxidation of acetylene on the NM surface, but irradiation has been performed with UVA, and thus TiO2 excitation must also be considered [124]. Interestingly, plasmonic photocatalysis using both functions of NMs, i.e., plasmonic excitation and inhibition of charge carriers' recombination, has been proposed by Rahul et al for bi-metalmodified TiO2-IO co-doped with N/F [106]. The LSPR excitation of Au results in an electron transfer from Au to CB of TiO2, and then to co-deposited Pt NPs, on which H2 evolution takes place, as shown in Figure 8.…”

“…It should be pointed out that co-catalyst is necessary for efficient H2 evolution on titania, and Pt is probably the most active co-catalyst for this reaction [5,126]. Interestingly, plasmonic photocatalysis using both functions of NMs, i.e., plasmonic excitation and inhibition of charge carriers' recombination, has been proposed by Rahul et al for bi-metal-modified TiO 2 -IO co-doped with N/F [106]. The LSPR excitation of Au results in an electron transfer from Au to CB of TiO 2 , and then to co-deposited Pt NPs, on which H 2 evolution takes place, as shown in Figure 8.…”