The trial comes almost two years after a prominent journalist said online that Mr. Liu had engaged in unscrupulous business deals. The journalist, Luo Changping, also accused him of threatening to kill his mistress and exaggerating his academic credentials. In December 2012, Mr. Luo, then the deputy editor of Caijing Magazine, wrote three posts on the Sina Weibo microblog platform detailing those accusations against Mr. Liu, whose mistress had contacted the journalist.

At the time, Mr. Liu was also the head of the National Energy Administration. He was stripped of that position in May 2013, the same month that Communist Party anticorruption agents announced that he was being investigated on suspicion of “grave violations of discipline.”

Mr. Liu has not been charged in connection with the accusations about the death threat or his credentials. But the bribery case gives the Chinese government yet another opportunity to show the public that it is committed to stamping out corruption. Mr. Xi has vowed to go after both senior and junior officials, or “tigers and flies” as he has put it, who are guilty of graft and other forms of misconduct that threaten to undermine confidence in the party.

But even as the anticorruption campaign has brought down high-ranking officials once thought to be untouchable, such as China’s former security chief Zhou Yongkang, the authorities have been making it increasingly difficult for muckraking citizens to expose official wrongdoing. In June, the government announced rules barring journalists from writing articles without their employers’ permission or setting up their own websites. Last month, new regulations on social media platforms barred users with public accounts from posting or reposting news about politics or current affairs without government approval.

Mr. Luo, the journalist, refused to comment on the trial when reached by telephone on Wednesday.

Despite the publicity surrounding Mr. Liu’s fall, many Chinese are skeptical that the anticorruption campaign is really about rooting out systemic abuses within the government. Zhu Ruifeng, a Beijing blogger who has detailed more than 50 cases of suspected corruption, dismissed the trial as political showmanship.