TY - JOUR A1 - Braun, Peter A1 - Durner, Bernhard A1 - Rabl, Hans-Peter A1 - Matysik, Frank-Michael T1 - Investigations on the decomposition of AdBlue urea in the liquid phase at low temperatures by an electrochemically induced pH shift T2 - Monatshefte für Chemie N2 - Ammonia-based selective catalytic reduction (SCR) systems are the most widely used technology for reduction of nitrogen oxide emissions from lean-burn engines such as diesel engines. However, at low exhaust temperatures, the SCR process is limited by difficulties in the decomposition of the ammonia precursor urea, which is carried on-board using an aqueous solution "AdBlue". In this study, the decomposition of AdBlue urea induced by electrical current and the resulting associated pH shifts were investigated in a divided cell configuration in the liquid phase. The decomposition was found to be favored in both electrochemical compartments, anodic and cathodic, at temperatures of 60-80 degrees C compared to a reference without electrochemical treatment. In addition to the determination of ammonia contents using an ammonia sensor, IC/HPLC analyses were carried out for each sample. Different side products such as biuret, nitrate, cyanuric acid, ammelide, and others were formed. In the anodic compartment, nitrate formation could be observed due to oxidation of ammonia at the electrode surface. [GRAPHICS] . KW - Ammonia KW - Catalysis KW - CONVERSION KW - Diesel Engine KW - DOPED MN/TIO2 KW - Electrochemistry KW - HYDROLYSIS KW - In situ pH shift KW - NOX KW - OXIDATION KW - PRODUCTS KW - REMOVAL KW - SCR KW - SELECTIVE CATALYTIC-REDUCTION KW - Thermochemistry Y1 - 2019 UR - https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/2538 VL - 150 IS - 9 SP - 1633 EP - 1641 PB - Springer ER -