Metal-free photocatalytic transformation of waste polystyrene into valuable chemicals: advancing sustainability through circular economy

Abstract

The present study offers a metal-free photocatalytic visible-light-driven protocol in addressing the plastic waste crisis. The reaction uses photocatalytic C-H bond activation to deconstruct polystyrene (PS) waste into valuable products...

Selective Hydrogenation of Cinnamaldehyde, Furanic, and Aromatic Aldehydes over a Z-Scheme Heterojunction Photocatalyst Constituted of Pd NPs Supported on g-C3N4/ZnO Nanocomposite

“…The comprehensive band architecture of g-C 3 N 4 , ZnO, and g-C 3 N 4(0.73) /ZnO (0.27) were investigated utilizing valence band X-ray photoelectron spectroscopy (VB-XPS), ultraviolet photoelectron spectroscopy (UPS), and DRUV−vis spectroscopy. 33,36,37 Examination of VB-XPS for g-C 3 N 4 and ZnO unveiled their valence band maxima positioned at 1.75 and 2.37 eV with reference to their respective Fermi levels (E f ) (Figure 6c,e). 31,62 The Fermi level in both g-C 3 N 4 and ZnO was associated with their work function (Φ), which characterizes the energy difference between the Fermi level and the vacuum level (Vac).…”

“…The photocatalytic process's efficiency assessment involved determining apparent quantum yield (AQY), employing a previously established methodology. 37,38 The comprehensive insights into the reaction, reactor setup, conversion rates, selectivity, and AQY calculations are provided to the SI. The SI also details the nitroblue tetrazolium test (NBT) and the terephthalic acid (THA) test.…”

“…The XRD of the pristine g-C 3 N 4 reveals a layered graphitic arrangement, where the (002) plane is evident at an angle of 27.41 (Figure 2a). 37,39 Furthermore, the (100) diffraction plane at 13.1°provides insights into the arrangement of stacked layers within the catalyst. The XRD pattern of ZnO displays characteristic peaks at 31.7°, 34.6°, and 36.5°(2θ values), corresponding to the crystallographic planes (100), (002), and (101) (JPCDS card number 36-1451) (Figure 2a).…”

“…33,47,48 Similarly, in ZnO, three types of oxygen�lattice oxygen, oxygen in vacant sites, and interstitial oxygen�are 4i). 36,37 The C 1s XPS analysis of 1%Pd@g- . Upon further examination of the N 1s spectrum of 1%Pd@g-C 3 N 4(0.73) /ZnO (0.27) , three peaks become apparent: one at 398.76 eV corresponding to pyridinic N, another at 399.99 eV representing NC 3 , and a third at 400.83 eV indicating NH x amine functional groups 49,50 The prevalence of pyridinic N in the N 1s spectrum is congruent with the constitution of pristine g-C 3 N 4 , which is obtained from urea and also manifests three distinct nitrogen species, each delineated by binding energies at 401.06, 399.99, and 398.62 eV.…”

“…For evaluating E a , the Arrhenius equation was employed, yielding a determined value of 42.40 kJ mol −1 (Figure S10d). 37 The reaction is driven by photogenerated charge carriers, which substantially influence the rate of the reaction. The reaction's pace is closely tied to the quantity of photogenerated charge carriers.…”