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In this study, the distribution of precious metals in waste printed circuit boards was investigated and the economic value of recycling was assessed. Contacts of pins, slots, interfaces and the board surface in waste printed circuit boards were analyzed, and three types of precious metals were detected. The content of gold, silver and palladium ranged from 179.86 mg/kg to 3694.51 mg/kg, 809 mg/kg to 12320.51 mg/kg and 96.25 mg/kg to 117.49 mg/kg, respectively. Gold was distributed wildly in contacts of many slots and all interfaces, while contacts of only two interfaces (the cable and USB) contained palladium. The highest content of Au was found in contacts of the cable. Silver mainly concentrated on pins (metal foil contacts) of electronic components and its highest content was found in microchips. The economic value of recyclable precious metals in 1 t waste printed circuit boards was up to 2292.94 dollars, of which Au contributed 98%. This study indicates the prominent economic benefits of precious metal recovery from waste printed circuit boards. Moreover, the scientific information provide guidance for the directional and accurate recovery of precious metals from waste printed circuit boards.

The elimination of volatile organic compounds (VOCs) via vacuum ultraviolet (VUV) photolysis is greatly limited by low removal efficiency and gaseous byproducts generation, while photocatalytic oxidation of VOCs suffers from catalytic deactivation. Herein, a coupled process of gaseous VUV photolysis with aqueous photocatalytic oxidation with P25 as the catalyst was firstly proposed for efficient aromatic VOCs removal (VUV/P25). The removal efficiency of toluene reached 86.2% in VUV/P25 process, but was only 33.6% and 58.1% in alone gaseous VUV photolysis and aqueous ultraviolet photocatalytic oxidation (UV/P25) process, respectively. Correspondingly, the outlet CO

As a kind of emerging pollutant, volatile organic compounds (VOCs) are getting increasing attention due to their contribution to the formation of atmospheric haze and O

Exploiting efficient and economical electrocatalysts for hydrogen evolution reaction (HER) is critical for sustainable energy systems. Herein we engineer a novel nanocomposite (RuP/NP-C) comprising ultrafine RuP nanoparticles encapsulated in N, P co-doped porous carbon derived from a well-defined Ru3+ incorporated phytic acid–polyaniline composite. Benefitting from its unique composition and architecture with full exposure of active sites, rapid mass/charge transfer, and improved structural robustness, RuP/NP-C nanocomposite can exhibit respectable HER performance. Significantly, from experimental and theoretical investigations, it is revealed that charge redistribution occurs due to interfacial electronic interaction between RuP and NP-C, leading to electronic modulation of RuP with upshift of the d-band center relative to Fermi level, thereby yielding optimal hydrogen binding strength for HER. This study highlights a promising route to tailor the electronic state of catalyst via interfacial electronic effect for boosted catalytic property.

Photocatalytic degradation of per- and polyfluoroalkyl substances (PFAS) remains insufficient. It is vital to investigate the structure–activity relationship between exposed facets and photocatalytic activity of PFAS. In this study, BiOCl nanosheets with predominantly exposed {0 1 0} or {0 0 1} facets (i.e. {0 1 0}-BiOCl or {0 0 1}-BiOCl) were synthesized via the hydrothermal method and applied for the photodegradation of perfluorooctanoic acid (PFOA). We observed that the degradation rate constant of PFOA via the {0 1 0}-BiOCl (0.0954 min−1) was 2.64-fold better than that of the {0 0 1}-BiOCl (0.0361 min−1) in photocatalytic activity. Density functional theory calculation results revealed that the higher catalytic activity of {0 1 0}-BiOCl was attributed to the in-situ generated surface oxygen vacancies (OVs) and the strong interaction with PFOA molecules via the bidentate adsorption configuration. {0 1 0}-BiOCl nanosheets with OVs exhibited the highest adsorption capacity (55.6 mg g−1h−1) and lowest adsorption energy (-0.399 eV) for PFOA molecules. The electron spin resonance spectroscopy and radical scavenging experiments showed that both photogenerated holes and surface hydroxyl radicals were generated on {0 1 0} facets that contributed to the degradation of PFOA; while only photogenerated holes were formed on {0 0 1} facets. Interestingly, F− ions as the by-products were prone to attaching to the BiOCl facets to block the catalytic sites. To recover the catalytic performance, we adopted a simple chemical precipitation approach to precipitate the F− by using Ca2+ ions. Our findings provide fundamental insights into the interface reactions during the photocatalytic degradation of PFOA.