Using xpath to access HTML within matching div

Question

I am trying to loop through a series of p tags on a source page. Within each p tag there will be formatted text, e.g. <p>hello, my name is <b>bob</b></p>

I would like to each hello, my name is <b>bob</b> but am currently only getting hello, my name is bob without the <b> tags.

I assume nodeValue is not the correct call but unsure what to use

$xpath = new DOMXPath($doc);
$row = $xpath->query('//div[@class="article-body"]/p');

foreach($row as $r) {
  echo $r->nodeValue;
}