Insight into the anti-corrosion mechanism of Pisum sativum L leaves extract as the degradable inhibitor for Q235 steel in sulfuric acid medium

•Electrochemical test data indicate Pisum sativum L leaves extract belong to mixed-type inhibitor.•The Pisum sativum L leaves extract adsorb on the Q235 steel surface in accordance with the Langmuir model.•Theoretical calculation provide in-depth understanding of the experimental results.