Electrocatalytic Upgrading of Lignin‐Derived Bio‐Oil Based on Surface‐Engineered PtNiB Nanostructure

Abstract

The development of robust electrocatalysts for electrocatalytic hydrogenation (ECH) of guaiacol and related lignin model monomers is necessary for the stabilization or upgrading of bio‐oil. Additionally, the efficiency of biomass conversion to bio‐oil products remains below the minimum requirements for its implementation at scale. Herein, a PtNiB/CMK‐3 catalyst with pronounced ECH performance in the conversion of guaiacol and related model lignin monomers to bio‐oil under optimally mild conditions, through a modulation strategy that modified the electronic structure of PtNi via boron alloying, is prepared. Notably, the optimized PtNiB/CMK‐3 exhibited an inspiring high faradaic efficiency of 86.2%, which is significantly higher (13.7 times) than that of the PtNi/CMK‐3 without B‐doping (6.3%). Experimental results and theoretical calculations showed that the B‐doping optimized the PtNiB alloy surface electron structure, simultaneously promoting substrate and intermediate adsorption and the ECH process. In addition, the uniform dispersion of PtNiB nanoparticles embedded within the mesoporous channels of CMK‐3 ensures an enhanced utilization efficiency, leading to improvements in stability and bio‐oil product generation. The lab‐scale ECH experiment of guaiacol also certified the scale‐up potential. This work opens a promising avenue to the rational design of advanced and highly efficient electrocatalysts for biomass upgrading.

Upgrading of Bio‐Oil Model Compounds and Bio‐Crude into Biofuel by Electrocatalysis: A Review

“…Electrode commonly consists of catalysts and conductive material (catalyst support), which has a crucial effect on the bio‐oil conversion and products selectivity in bio‐oil ECH process. In detail, electrocatalysts like noble metal, [32b,33,39b,48] base metal, [32a,48a,c,49] alloy, [9a,50] oxide [51] and phosphide [40a] have been reported for upgrading bio‐crude and model compounds by ECH. Besides, graphite, activated carbon and other porous materials as catalyst supports can improve the electrocatalytic performance.…”

“…Recently, alloy was found active for ECH. Zhou et al [9a] . prepared a boron‐doped PtNiB/ordered mesoporous carbon (CMK‐3) cathode, which was further applied in ECH process (current: 20 mA, temperature: 60 °C) for guaiacol conversion and KA oil (a mixture of cyclohexanol and cyclohexanone) generation.…”

“…Thus, ACF was supposed as a good electrocatalyst carrier due to its large surface area and high conductivity [49c] . At present, graphite, [59] carbon felt, [32b] ACF, [39b] activated carbon cloth (ACC), [25b] carbon fiber cloth, [40a] ordered mesoporous carbon (OMC, CMK‐3), [9a,54] and other conductive materials have been used as catalytic carriers to enhance ECH activity. Particularly, insulating materials such as aluminum oxide (Al 2 O 3 ) were also used as support of electrocatalysts because of the slurry nature of electrochemical dynamic cell [60]…”

“…However, different result was also reported. Zhou et al [9a] . investigated the reduction rate of guaiacol on PtNiB/CMK‐3 cathode in the same electrolytes (0.2 M H 2 SO 4 , HClO 4 , HCl) (temperature: 50 °C, current: 20 mA) [49c] .…”

Greener Routes to Biomass Waste Valorization: Lignin Transformation Through Electrocatalysis for Renewable Chemicals and Fuels Production

“…SPE electrolyzersc an either adopt ab atch style, where electrolyte is recirculated back to the compartment,o r be run in af low style, where electrolyte goes through as ingle stream.I na ddition to omitting the use of supporting electrolyte, SPE electrolyzers offer greater energy savings as both electrodes are at the closestp roximity with one another,w hich reduces the potential requiredt oo vercome internal resistance. Severale xamples have demonstrated the feasibility of SPE electrolyzers for model substrates such as acetone, [200] benzyl alcohol, [201] 5-HMF, [202] furfural, [52,203] bio-oil, [204,205] soybean oil, [206] and others. [199,207,208] Although none are related to direct electrocatalysis of lignin polymers, these studies are great ex-amplesf or designing as oluble electrolyte-free biomass upgradingr eactor.…”